Prime Minister Benjamin Netanyahu of Israel said the cease-fire would end if Hamas did not release captives held in Gaza. But he did not say how many hostages had to be freed.

The first phase of the ceasefire between Israel and Hamas is supposed to last six weeks. But three weeks in, both Israel and Hamas are accusing the other of violating the deal, and Hamas’ threat to delay freeing more hostages has prompted Israel to prepare to resume fighting if needed.