Hamas is an Islamist militant movement and one of the two major political parties in the Palestinian territories. It emerged in 1987 during the first Palestinian uprising as an outgrowth of the Muslim Brotherhood’s Palestinian branch. Hamas is committed to armed resistance against Israel and the creation of an Islamic Palestinian state in Israel’s place. Hamas has been the de facto governing body in the Gaza Strip since 2007, when it ousted the Palestinian Authority from power. Hamas has a military wing known as the Izz al-Din al-Qassam Brigades that has conducted many anti-Israel attacks in both Israel and the Palestinian territories since the 1990s. These attacks have included large-scale bombings against Israeli civilian targets, small-arms attacks, improvised roadside explosives, and rocket attacks. Hamas uses improvised explosive devices, short- and long-range rockets and mortars, small arms, kidnapping operations, rocket-propelled grenades, man-portable air defense systems, antitank missiles, and unmanned aircraft systems in attacks against Israeli military forces and civilians, as well as against ISIS and other Salafist armed group members based in Gaza.

Gaza is a 41km-long and 10km-wide territory between Israel, Egypt, and the Mediterranean Sea. It is home to about 1.6 million people and has one of the highest population densities in the world. Israel controls the airspace over Gaza and its shoreline and restricts who and what goods are allowed in and out through its border crossings. Similarly, Egypt controls who passes in and out through its border with Gaza. About 80% of the population of Gaza depends on international aid, according to the UN, and about one million people rely on daily food aid. There is constant tension between Israel and Hamas, but the attack by Hamas on Saturday came without warning. Hamas fired thousands of rockets.