The Palestinian group Hamas carried out a surprise attack on southern Israel from Gaza on Oct. 7, killing 1,200 people and seizing about 250 hostages in the deadliest day in Israel's history, according to Israeli tallies.
It triggered an Israel-Hamas war that has seen the heaviest Israeli bombardment of Gaza in 75 years of conflict. More than 25,000 Palestinians have been killed in Israeli strikes on Gaza, according to health authorities in the Hamas-run Gaza Strip, who say thousands more dead are feared lost in the rubble.
WHAT IS HAMAS?
Hamas is an acronym of the Arabic phrase "Islamic Resistance Movement". It was founded in 1987 by the Muslim Brotherhood during the first Palestinian Intifada, or uprising.
It is designated a terrorist group by Israel, the United States, the European Union, Britain, Canada and Japan. Hamas characterizes its armed activities as resistance against Israeli occupation.
WHAT DOES HAMAS WANT TO ACHIEVE?
Hamas' 1988 founding charter called for the destruction of Israel, although Hamas leaders have at times offered a long-term truce, or Hudna in Arabic, with Israel in return for a viable Palestinian state on all Palestinian territory occupied by Israel in the 1967 war. Israel regards this as a ruse.
The group refuses to recognise Israel, and violently opposed the Oslo peace accords negotiated by Israel and the Palestine Liberation Organization (PLO) in the mid-1990s.
While Hamas wants all the land between the Mediterranean Sea and the River Jordan, which includes the modern state of Israel as well as the occupied West Bank and Gaza, in 2017 it said it might accept a transitional solution.
In a document issued on May 1 that year by its outgoing chief Khaled Meshaal, Hamas said it agreed to a transitional Palestinian state within frontiers pre-dating the 1967 war, although it still opposed recognizing Israel's right to exist or ceding any Palestinian rights. One of Hamas' most senior officials, Mahmoud al-Zahar, later said the document was not a substitute for its founding charter.
HOW DID HAMAS COME TO POWER?
Hamas won Palestinian parliamentary elections in 2006 – the first time it took part, and the last time they were held. It took over the Gaza Strip in 2007 after a brief civil war in which it routed the western-backed Palestinian forces loyal to Hamas's domestic rival President Mahmoud Abbas.
Abbas is based in the West Bank and heads the more secular Palestine Liberation Organization and the PLO's dominant party, Fatah.
Abbas described the Gaza takeover as a coup. Hamas accused Abbas of conspiring against it.
Since then, there have been numerous rounds of conflict with Israel, often involving Hamas rocket attacks from Gaza into Israel and Israeli airstrikes and bombardment of Gaza.
WHO ARE THE HAMAS MILITANTS?
Hamas' armed wing is called the Izz el-Deen al-Qassam Brigades. It has sent gunmen and suicide bombers into Israel and fired thousands of rockets and mortar shells.
The military wing is highly secretive and is run by Mohammed Deif, who masterminded the Oct. 7 attack on Israel.
It has bases all over Gaza, but also members across the Israeli-occupied West Bank and farther afield. Many of its leaders and fighters are now thought to be fighting Israel's ground forces in Gaza from an underground network of tunnels.
WHO IS FUNDING HAMAS?
Although a Sunni Muslim group, Hamas is part of a regional alliance comprising Iran, Syria and the Shi'ite Islamist group Hezbollah in Lebanon, which all broadly oppose U.S. policy in the Middle East and Israel.
While its power base is in Gaza, Hamas also has supporters across the Palestinian territories, and it has leaders spread across the Middle East in countries including Qatar.
It has received money, weapons and training from Iran, but also has a global fund-raising network, which it uses to funnel support from charities and friendly nations, passing cash through Gaza tunnels or using cryptocurrencies to bypass international sanctions, according to experts and officials.
The U.S. State Department said Hamas raises funds in other Gulf countries and gets donations from Palestinians, other expatriates and its own charities.
Matthew Levitt, a former U.S. official specialised in counterterrorism, estimated that the bulk of Hamas' budget of more than $300 million came from taxes on business, as well as from countries including Iran and Qatar or charities.
A Qatari official said late last year that Qatar's aid to Gaza was delivered directly to families needing essentials such as food and medicine, under strict guarantees to ensure it reaches affected civilians. The distribution is coordinated with Israel, U.N. agencies and the United States, the official said.
