5 things to know as Israel declares war on Hamas following the militant group's unprecedented attack

Fire and smoke rise following an Israeli airstrike, in Gaza City, Sunday, Oct. 8, 2023. The militant Hamas rulers of the Gaza Strip carried out an unprecedented, multi-front attack on Israel at daybreak Saturday, firing thousands of rockets as dozens of Hamas fighters infiltrated the heavily fortified border in several locations, killing hundreds and taking captives. Palestinian health officials reported scores of deaths from Israeli airstrikes in Gaza. (AP Photo/Fatima Shbair)

Israel declared war Sunday as it bombarded the Gaza strip with airstrikes in retaliation for a major surprise attack by Hamas.

The declaration came a day after an unprecedented incursion by Hamas fighters who blew through a fortified border fence and gunned down civilians and soldiers in Israeli communities along the Gaza frontier during a major Jewish holiday.

As many as 1,000 Hamas fighters took part, U.S. Secretary of State Antony Blinken said. The rampage included an assault on a crowded music festival where authorities had removed about 260 bodies by Sunday.