What is Hamas, and why did it attack Israel now?

Israel declared war against Hamas on Sunday following a surprise attack by the Palestinian militant group based in Gaza that included the taking of military and civilian hostages. Israeli security forces, caught off guard, have pounded the Gaza Strip with retaliatory strikes, and U.S. officials said they expect Israel to soon launch a ground incursion into the enclave as violence escalates in the conflict-ridden region.

Since winning legislative elections in 2006, Hamas has repeatedly attacked Israel with rockets and mortars, emerging as a defiant adversary. Israel has retaliated with its superior firepower and a punishing blockade, restricting imports and the movement of civilians in a strategy of collective punishment. The blockade and recurring Israeli strikes have contributed to Gaza’s poor infrastructure and living conditions. Israel declared a full siege of the enclave on Monday, with Defense Minister Yoav Gallant promising “no electricity, no food, no fuel” and calling Hamas militants “savages.”

[The Gaza Strip and its history, explained]

Here’s what to know about Hamas and the latest violence.

What is Hamas?

Hamas, or the Islamic Resistance Movement, is a militant group that governs the Gaza Strip, a 25-mile-long, densely populated enclave of more than 2.1 million people. Hamas emerged in 1987 as an offshoot of the Muslim Brotherhood during the first Palestinian intifada, or uprising, against the Israeli occupation of Gaza and the West Bank. It was founded by Sheikh Ahmed Yassin, a Palestinian cleric. Its military wing, the Izzedine al-Qassam Brigades, was established around 1991.

Unlike the Palestinian Authority, Hamas does not recognize the existence of Israel and is committed to replacing it through armed struggle with a Palestinian state stretching from the Mediterranean Sea to the Jordan River.

In October 1997, the United States designated Hamas a terrorist organization. The group, supported by Iran, has used explosives and rockets, along with suicide bombings and kidnappings, to target Israel.

Hamas won elections in Gaza in 2006, defeating Fatah, the main Palestinian party that still controls the West Bank.

Israel has targeted Hamas leaders over the years. In 1997, Khaled Meshal, a top official, survived an assassination attempt by the Mossad, Israel’s national intelligence agency, which poisoned him in Amman, Jordan. Meshal was saved after Jordan detained the Israeli agents and President Bill Clinton pressed Israel to hand over the antidote.

Israel assassinated Yassin and another founding member, Abdel Aziz Rantisi, in 2004 and killed Hamas military chief Ahmed Jabari in November 2012.

Why did Hamas attack Israel now?

The coordinated attack by Hamas caught Israel by surprise but comes after months of worsening tensions over violence at al-Aqsa Mosque - a sacred Muslim site in the heart of Jerusalem located on the same spot as the Temple Mount revered by Jews - as well as the punishing blockade and occupation of Palestinians. The presence of once-fringe Jewish supremacists and settler leaders in Prime Minister Benjamin Netanyahu’s hard-right government have further inflamed tensions with the Palestinians, as well as caused domestic strife inside Israel that has led to a perception of weakness.

Palestinian anger also reached a boiling point in May 2021 over the proposed evictions of families from a Palestinian neighborhood in East Jerusalem, leading to clashes between protesters and Israeli forces that prompted Hamas to launch rockets at Israeli cities.

In the months leading up to Saturday’s surprise attack, clashes had increased between Israeli forces and Palestinians, particularly in the West Bank. Between January and September, 227 Palestinians were killed by Israeli forces or settlers - more than the number in all of 2022, according to the United Nations. Israeli fatalities, before the latest violence, totaled at least 29.

During the Muslim holy month of Ramadan, in April, Israeli forces stormed al-Aqsa Mosque in Jerusalem and used force on worshipers, including women and the elderly, and Israeli police last week guarded a group of settlers marching through the area. Both Muslims and Jews, which call the mosque the Temple Mount, consider the site among the holiest in their respective faiths.

A five-day conflict broke out in May between Israel and Islamic Jihad, another armed Palestinian faction, killing at least 33 in Gaza and two in Israel.

Over the summer, clashes broke out between Palestinian militants in the West Bank and Israeli forces or Jewish settlers. In June, four Israelis were killed after two Hamas gunmen opened fire at a hummus restaurant outside an Israeli settlement. Days later, Israel carried out its most expansive military operation in two decades in the West Bank when it stormed the city of Jenin with about 1,000 soldiers backed by drone strikes. Calling it a “counterterrorism” effort, Israel focused the operation on the impoverished Jenin refugee camp, known to be a hub of armed factions, many with links to Hamas and Islamic Jihad.

Tensions in Gaza nearly spilled over in September after Israeli agents found explosives in a shipment of jeans and ended all exports from the enclave. In response, Hamas held field exercises, including practice rocket launches, and allowed Palestinians to protest at the border fence separating Israel and Gaza.

Even as Netanyahu’s government has contended with the violence, hundreds of thousands of Israelis have regularly taken to the streets since spring in demonstrations against policies his right-wing coalition has pushed. The result, some analysts have speculated, has been Israeli inattention to national security and activities inside Gaza, leading to what has been widely portrayed as a massive intelligence failure.

In calls Sunday to leaders of Hamas and the Islamic Republic, another Islamist group inside Gaza, Iranian President Ibraham Raisi said that “Israel is in decline,” according to Iranian media reports.

In comments since the attacks, Iranian officials have made specific warnings to Arab countries trying to normalize relations with Israel. In an apparent reference to Saudi Arabia, Ali Akbar Velayati, a senior foreign policy adviser to Supreme Leader Ali Khameini, warned “certain governments in the region to learn a lesson from the fate of the countries that have followed the [normalization] path,” according to Iran’s Mehr news agency. Speaking to Syria’s foreign minister, the report said, Velayati also warned against participation in the Biden administration’s proposed economic rail and sea corridor stretching through the Persian Gulf countries from India to Europe.

How is Hezbollah involved?

On Sunday, Hezbollah, Lebanon’s Islamist militant group and a major political party, said it attacked Israeli targets in Shebaa Farms, a disputed area on the border, “in solidarity” with Hamas, prompting retaliation from Israel. While the group did not say it was formally joining the fight, its message of support raised the likelihood of a wider regional conflict.

Hezbollah has long been seen as a more dangerous opponent of Israel than Hamas, with more sophisticated weaponry and closer ties to Iran.

“Our hearts are with you. Our minds are with you. Our souls are with you. Our history and guns and our rockets are with you,” top Hezbollah official Hashem Safieddine said at a rally in Beirut on Sunday, in reference to Hamas.

While Palestinian factions in recent years have used Lebanese territory to attack Israel, Hezbollah’s behavior had indicated it aimed to avoid escalation, and attacks were usually limited, often targeting uninhabited lands. But Sunday’s moves of trading fire and public comments suggest it does not intend to remain on the sidelines.

Israel requested cooperation with the United States on sharing intelligence related to southern Lebanon, officials told The Washington Post.