The deal to bring an end to the fighting in Gaza is on the brink of collapsing — and there is no clear immediate alternative agreement that could be put forward in its place, according to two U.S. and two Israeli officials.

Both Israel and Hamas also disagree over Israel’s presence in both the Philadelphi Corridor, a stretch of land on the Egypt-Gaza border, and in a main throughway that leads to northern Gaza. Israel has said it wants to maintain its position in both places to ensure Hamas cannot smuggle goods in through Egypt and reposition its strongholds.