Israel said the Tuesday attacks were launched after Hamas refused to release more hostages held in Gaza. The strikes raise the prospect of a full resumption of war after a nearly two-month ceasefire.

DEIR AL-BALAH, Gaza Strip (AP) — Israel launched airstrikes across the Gaza Strip early Tuesday, killing at least 400 Palestinians, mostly women and children, according to local health officials. The surprise bombardment, the deadliest in Gaza since the start of the 17-month war, shattered a ceasefire in place since January.

Israel launched a large-scale military operation centered on Jenin shortly after reaching a fragile ceasefire with Hamas in the Gaza Strip in January. Troops have destroyed homes and infrastructure, and tens of thousands of Palestinians have fled their homes across the northern West Bank.