Local health officials said Israeli strikes killed at least 85 Palestinians across he Gaza Strip overnight and into Thursday, bringing the total to nearly 600 killed since Israel shattered a truce that had facilitated the release of more than two dozen hostages and brought relative calm since late January.

Prime Minister Benjamin Netanyahu’s office said he had ordered the aerial attacks after Hamas’s “repeated refusal” to release the remaining hostages it holds. “This is just the beginning,” he said.

Israeli airstrikes pounded Gaza, killing more than 400 people, Palestinian health authorities said on Tuesday — collapsing a two-month ceasefire with Hamas as Israel vowed to use force to free its remaining hostages in the territory.