Israel conducted a speedy investigation and took responsibility for the deaths, but said the attack that killed the aid workers and their Palestinian driver was a tragic mistake.

The deaths threaten to strain the internationally mediated cease-fire talks, which appeared to gain steam in recent days even as the sides remain far apart on key issues.

Israel strongly denies its military campaign amounts to breaches of the Genocide Convention.

The discovery renewed pressure on Israel’s government for a deal to get the remaining hostages freed. Families have long feared time is running out.