Sunday's delayed start to the Gaza ceasefire and incidents on Monday, in which Israeli troops shot at Palestinians approaching them, underline some of the hiccups likely to face a deal that will play out in the shadow of mutual mistrust and bitterness.

Qatar and Egypt, which brokered the deal alongside the U.S., have set up a communications hub to tackle any problems, where officials who worked on the deal for months hope to head off new clashes between foes locked in a yearslong cycle of Gaza wars.

"These kinds of deals are never easy to maintain," said Majed Al-Ansari, spokesperson for Qatar's foreign ministry.