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.

Israeli strikes killed at least five Palestinians in the Gaza Strip, health officials in the enclave said, and the Israeli army said it targeted a Hamas military site in the north.

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.