Meanwhile, the U.N. Food Program said 77 trucks carrying aid were stopped by hungry people who took the food before the trucks were able to reach their destination.

Officials said Hamas was seeking changes on guarantees for a permanent end to war. That has long been the core sticking point with Israel.

The latest friction in negotiations comes as the fighting nears 20 months of war, and as desperation grows among hungry Palestinians and relatives of hostages in Gaza.