When Hamas terrorists launched a shocking assault on Israel on October 7, 2023, taking hostages and killing hundreds, it reignited a bitter and intractable conflict.
The devastating Israel-Gaza war that has followed has stoked further violence in countries such as Lebanon and Jordan and in the Red Sea, fuelling fears of a wider war in the Middle East.
The US is the latest nation to launch air strikes, targeting sites in Iraq and Syria in retaliation for three of its troops being killed a week earlier.
At the centre of the unfolding crisis is a decades-long battle between Israelis and Palestinians over territory and sovereignty.
It is impossible to explain the entire history of occupation, oppression and bloodshed in the region in one concise article.
What we can try to do is provide some background, explain what's happening at the moment, and contextualise the position of key actors in this escalating war.
Why is the war escalating?
There are two relevant forces in the Middle East that have been at odds for years and they're backing opposite sides of the Israel-Gaza war.
On the one hand, you've got the powerful Israel-US allies, who have strategic ties to Saudi Arabia and want to stop Iran's coalition from gaining a foothold in the region.
On the other hand, you've got what Iran calls the Axis of Resistance. It's a military network of state and non-state actors that oppose Israeli and American power in the Middle East.
Militants spread across the region such as Hamas, Hezbollah, the Islamic Resistance in Iraq and the Houthis are all part of this Iran-funded group.
The Israel-Gaza war began escalating when Hamas' Iran-backed allies in other countries attacked Israeli and non-Israeli targets, prompting the US military to intervene.
The so-called Axis of Resistance has claimed more than 150 attacks on US targets in the region since October 7. However, the first deadly strike was on a US base in Jordan on January 29. The Pentagon believes yet another Iran-backed militant group, the Islamic Resistance in Iraq, was responsible.
These widespread clashes have been taking place in the context of other conflicts between — and within — countries, which is complicating alliances and roping more actors into the war.
So how are these key actors involved?
Read on and click on each card below to find out more.
ISRAEL
The state of Israel comprises nearly 10 million people. It is headed by long-serving Prime Minister Benjamin Netanyahu who has established one of the most right-wing governments in the country's history.
Israel was established in 1948 after the United Nations (UN) adopted a plan to divide the area that was then known as "Mandatory Palestine" into Jewish and Arab states. The Arab world rejected the partition, resulting in a full-blown war and the permanent displacement of more than half of the Palestinian population.
In the next war in 1967, Israel extended its control of surrounding territory further, establishing the military occupation of the West Bank, Gaza and East Jerusalem. There were several more rounds of hostilities and wars in the decades that followed before Palestinians in occupied territory were given limited autonomy to self-govern under the 1993 Oslo Accords.
Since then, the international community has long worked to establish an independent Palestinian state but that hasn't happened. The militant Palestinian group Hamas rejected the Oslo peace deal and it continues to push for a "fully sovereign" Palestinian state that would replace Israel as a political entity.
Israel is also opposed to a two-state solution, saying it needs "full security control" over Gaza, the West Bank and East Jerusalem. The UN still considers these areas to be part of a single Occupied Palestinian Territory.
Israel Defense Forces
What is it?
The Israel Defense Forces (IDF) is the national military of Israel and receives most of its imported weapons from the United States.
How is it involved?
Israel's military formally went to war with Gaza's ruling entity, Hamas, after the armed militant group attacked southern Israel on October 7. More than 1,200 Israelis and foreigners were killed in the terrorist assault, and about 240 hostages were reportedly taken to Gaza.
The IDF has been pounding Gaza with air strikes and battling Hamas fighters on the ground for months, with Israel vowing to continue until the surviving hostages are freed and Hamas is "eliminated" from the region.
Israel says it has killed 9,000 militants in total and it has lost 220 of its own soldiers. According to Gaza health officials, more than 26,000 Palestinians have been killed in the war and thousands more are feared lost in the rubble. The ABC cannot independently verify these figures.
Israel's military has also exchanged attacks with Hezbollah militants from Lebanon and the Houthis from Yemen, who have declared support for Hamas.
Hostages
How are they involved?
When Hamas launched its October 7 terrorist attack, Israel says the militant group abducted about 240 people and took them back to Gaza. More than 100 hostages were released during a brief truce in November. It's not clear exactly how many of those who remain in Gaza are still alive.
At least 23 hostages have been declared dead by Israeli officials, including three captives who were mistakenly shot by the Israeli military. Israel says it won't pull its military troops from Gaza until all of the surviving hostages are freed.
The people taken captive were a mix of Israelis and foreigners, soldiers and civilians, including men, women, children and the elderly. Their families have been calling for their safe return home.
Israeli ally: United States
How is it involved?
The United States is a long-term ally and the largest supplier of military aid to Israel, supporting the war against Hamas.
It is a key powerbroker in the conflict and has long supported a two-state solution that envisions the creation of an independent Palestinian state alongside Israel.
The US has diplomatic relations with every other country in the Middle East except Iran and Syria. It has provided support for the Saudi-led forces in Yemen against the Iran-backed Houthi fighters who have been the effective government since a 2022 ceasefire.
In January, the US launched retaliatory air strikes at Houthi targets inside Yemen after the militants fired missiles and drones towards Israel, as well as ships in the Red Sea, in support of Hamas.
The first deadly strike against US forces since the Israel-Gaza war erupted took place in January on a US base in Jordan, killing three troops. The Pentagon believes another Iran-backed militant group, the Islamic Resistance in Iraq, was responsible.
The US has hit more than 85 targets in Iraq and Syria linked to Iran's Revolutionary Guard Corps in retaliation.
GAZA (Palestinian territory)
Gaza is part of the Occupied Palestinian Territory, which also comprises the West Bank and East Jerusalem. It is ruled by Hamas and is home to more than 2 million Palestinians. Israel has imposed a blockade on Gaza, controlling most of the goods and people travelling to and from the narrow strip.
Iran backed: Hamas
What is it?
Hamas is the political party that governs the Palestinian territory of Gaza and its main objective is to create a Palestinian Islamic state. The group also has an armed militant wing called Izz ad-Din al-Qassam Brigades, which is funded mostly by Iran.
Hamas was founded in 1987 with the overarching goal of "liberating Palestine" by establishing an independent Palestinian state and destroying Israel as a political entity in the process. It does not recognise Israel and remains committed to fighting it.
Hamas took control of Gaza in 2007 after winning local elections and ousting its rival political party Fatah by force. The entire group is deemed a terrorist organisation by Australia, the US, Israel and the European Union.
How is it involved?
Hamas carried out the October 7 terrorist attacks in southern Israel that killed more than 1,200 Israelis and foreigners. The group also took about 240 hostages back to Gaza, triggering Israel's ongoing military offensive in the territory.
Hamas released half of the hostages after a brief November truce and exchange of captives for Palestinians held in Israeli prisons. But it insists it will not release any of the remaining hostages until the fighting in Gaza ceases for good.
In its 1988 charter Hamas called for the destruction of Israel. A 2017 update to the document calls for the "complete liberation of Palestine from the river to the sea". It also says that "without compromising its rejection of the Zionist identity" it would see a Palestinian state with borders as they were prior to the 1967 war as a "formula of national consensus".
Iran backed: Palestinian Islamic Jihad
What is it?
The Palestinian Islamic Jihad (PIJ) is the second-largest armed group in Gaza after Hamas. Although the two share the same objective of establishing a Palestinian Islamic state, the PIJ is not interested in political governance and it occasionally clashes with Hamas over tactics and strategy. The Iran-backed terrorist group also operates from the Palestinian territory of the West Bank, Lebanon and Syria.
How is it involved?
PIJ operatives helped Hamas carry out the terrorist attacks on southern Israel on October 7. Israel also blamed PIJ for a deadly explosion at a Gaza hospital in October, but the group denied it was launching rockets at the time.
Palestinian civilians
How are they involved?
According to Gaza's health ministry, women and children account for 70 per cent of the Palestinian death toll in Gaza.
The ministry says more than 26,000 Palestinians have been killed in total since the start of the war and another 65,000 have been injured.
The ministry does not distinguish between civilians and combatants but it estimates women and children account for 70 per cent of those killed in Gaza. Thousands more are reportedly missing and are presumed to be buried under rubble.
About 1.7 million Palestinians have also been displaced, the United Nations (UN) says. Significant damage has been inflicted on critical infrastructure and essential services, creating a humanitarian crisis.
With the flow of aid such as food and medicine into Gaza at just a trickle of pre-conflict levels, the UN says there is a growing risk of deaths from preventable diseases and famine.
WEST BANK (Palestinian territory)
The West Bank is part of the Occupied Palestinian Territory, which also comprises Gaza and East Jerusalem. It is partially governed by Fatah and is home to more than 3 million Palestinians. Israel retains full control of most of the area under the Oslo Accords.
Fatah
What is it?
Fatah is a secular (non-religious) political party that leads the Palestinian Authority, which was created after the 1993 Oslo Accords to have partial administrative control of the West Bank. Fatah is also a major faction of the Palestinian Liberation Organisation (PLO), an umbrella organisation comprising several political parties that claim to represent Palestinians worldwide.
Fatah also used to govern Gaza but the Palestinian Authority lost the 2006 elections to Hamas and the group was violently ousted in 2007 after it refused to cede control. While Hamas and Fatah both want to establish a Palestinian state, Fatah recognises Israel and uses diplomacy instead of violence to further its aims.
How is it involved?
The president of the Palestinian Authority, Mahmoud Abbas, has been a mediating voice during the conflict, advocating for a Gaza truce to ease the humanitarian crisis. Fatah supports a two-state solution that envisions the creation of a Palestinian state alongside Israel.
Israeli settlers
How are they involved?
UN figures show daily attacks against Palestinians by Israeli security forces and settlers in the West Bank have more than doubled since October 7.
Australia's Department of Foreign Affairs and Trade (DFAT) said in early December there had been 343 violent attacks in the West Bank, killing eight Palestinians and injuring dozens more, as well as forcing more than 1,000 people from their homes.
Australia joined more than a dozen other countries and the European Union in condemning the attacks. It reiterated that Israeli settlements in the occupied territory are illegal under international law.
IRAN
Iran is one of the major powers in the region, leading a military alliance of state and non-state actors in the struggle for dominance against Israel and the US.
Iran has denied any involvement in the October 7 attacks on Israel but it supports the Palestinian militant groups Hamas and Palestinian Islamic Jihad. It also supports the Houthi fighters in Yemen, who have attacked Israel-US targets in the Red Sea and the Gulf of Aden.
The US has also accused Iran's militant network of being behind the January attack on the US base in Jordan that killed three service members. It says it believes the Islamic Resistance in Iraq was responsible. Iran has denied any involvement.
The US military launched retaliatory air strikes in Iraq and Syria against more than 85 targets linked to Iran's Revolutionary Guard Corps (IRGC) but did not attack any locations inside Iran. The IRGC is a paramilitary group that is independent of Iran's conventional military force.
LEBANON
Lebanon shares its southern border with Israel and has a pre-existing dispute with it over territory. However, they are not at war. Militant group Hezbollah is based in Lebanon and has launched strikes against Israel since October 7 in support of its Hamas ally.
Iran backed: Hezbollah
What is it?
Hezbollah is an Iran-backed political and militant group based in Lebanon. It was formed in 1982 to fight against the Israeli occupation of southern Lebanon. It is now part of the Lebanese government coalition.
The entire group is deemed a terrorist organisation by Australia, the US, and Israel, while the European Union only designates the military arm of Hezbollah as a terrorist entity.
How is it involved?
Hezbollah has backed its Palestinian ally Hamas and exchanged fire and air strikes with Israeli forces across Lebanon's southern border since the start of the war. Hezbollah also accused Israel of assassinating Hamas leader Saleh al-Arouri in Lebanon's capital, Beirut, in early January. Israel has neither confirmed nor denied it was responsible for the killing.
YEMEN
Yemen has been locked in a bloody civil war between Saudi-backed forces and the Iran-backed Houthi movement since 2014. The Houthis announced their support for Hamas after October 7, launching strikes against Israel-US targets in the Red Sea.
Iran backed: Houthis
Who are they?
The Houthis are mountain fighters who have been battling Saudi-led forces for control of Yemen. They have been the de facto government in north Yemen since a 2022 ceasefire. The group has a large arsenal of armed drones and ballistic missiles largely supplied by Iran. Yemen's civil war is widely seen as a proxy war between Saudi Arabia and Iran.
How are they involved?
The Houthis have repeatedly launched missiles and drones from Yemen, targeting Israel and shipping vessels in the Red Sea. The US has thwarted most of the attacks and carried out retaliatory strikes, in coordination with the UK, on Houthi bases in Yemen.
The Houthis have subsequently attacked US targets in the Gulf of Aden, which flows into the Red Sea. Major shipping companies have been forced to divert and use a much longer route around southern Africa, delaying shipments and raising the cost of goods.
SAUDI ARABIA
Saudi Arabia is another one of the major powers in the region. It has been at odds with Iran for years due to opposing interests. The two countries signed a deal to normalise ties last year but Saudia Arabia continues to lead Yemen's military coalition against the Iran-backed Houthis.
Saudi Arabia has never formally recognised Israel and a potential normalisation of ties between the countries, brokered by the US, was put on ice after October 7. Saudi Arabia says there can be no normal relationship between them without the creation of an independent Palestinian state.
EGYPT
Besides acting as a mediator in the conflict, Egypt shares a very important border with Gaza, which includes the Rafah Crossing. Egypt was the first Arab country to recognise Israel and it is close allies with Saudi Arabia. It has an uneasy relationship with Hamas and the Palestinian factions in the West Bank.
Rafah Crossing
Why is it important?
The narrow Rafah Crossing controlled by Egypt has been a vital corridor for transporting humanitarian aid to Palestinians in Gaza since the start of the war.
The crossing is also where Palestinians who hold dual nationality have been allowed to evacuate the territory, but Egypt refuses to take in Palestinian refugees displaced by the war.
JORDAN
Jordan shares its western border with Israel and the West Bank territory, and at least half of its population is of Palestinian origin.
In January, three US service members were killed and about another 40 were injured in a drone attack on a US base in Jordan. The Pentagon believes an Iran-backed militant group in Iraq is responsible.
Jordan fears the Gaza conflict could lead to wider violence by Israeli settlers in the West Bank and trigger a large-scale exodus of Palestinians into Jordan. It supports a two-state solution and is a strategic ally of the US.
IRAQ
The US says the Islamic Resistance in Iraq was responsible for the drone strike on a US base in Jordan in January. This attack, which killed three troops, was the most deadly one among dozens of other attacks the group has carried out on US targets in the Middle East since October 7. The US has struck targets in Iraq in retaliation.
Iran backed: Islamic Resistance in Iraq
What is it?
The Iran-backed Islamic Resistance in Iraq (IRI) is an umbrella organisation that comprises other armed groups, including Kataib Hezbollah.
How is it involved?
The US believes the IRI planned, resourced and facilitated the fatal attack on the US base in Jordan. The group has not openly confirmed or denied involvement in this incident.
IRI has claimed more than 150 attacks on bases housing US forces in Syria and Iraq since October, leading to dozens of mostly minor injuries and drawing several rounds of US strikes in response.
It says these actions are part of an effort to "resist American occupation forces" and had been carried out in "response to the massacres" committed by Israel against Palestinians in Gaza.
SYRIA
Iran has accused Israel of striking a building in Syria's capital, Damascus, killing five Iranian Revolutionary Guards on January 20. There has been no comment from Israel, which has long pursued a bombing campaign against Iran's military and security presence in Syria but typically does not discuss such attacks publicly.
The US has also struck Iran-linked targets in Syria in retaliation for the fatal attack on a US base in Jordan by an Iran-backed militant group.
QATAR
Qatar has played a key mediating role in the conflict because of its deep ties to Hamas. It hosts some of the militant group's exiled leaders and has transferred funds to Gaza in recent years. Qatar helped secure the week-long truce in November during which more than 100 hostages were released from Gaza.
It is now involved in negotiating another deal between Hamas and Israel to release the remaining hostages.