Israeli airstrikes pounded Gaza and killed more than 400 people, Palestinian health authorities said, shattering nearly two months of relative calm since a ceasefire began, as Israel warned the onslaught was "just the beginning.

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.

Israel launched airstrikes across the Gaza Strip early Tuesday, killing more than 400 Palestinians, local health officials said, and shattering a ceasefire in place since January with its deadliest bombardment in a 17-month war with Hamas.