The group said that mediators were working “to remove obstacles and close gaps” after the cease-fire deal with Israel hit a roadblock. Israel has yet to comment.

As Israel and Hamas accuse each other of violating the cease-fire deal, Israel’s prime minister has vowed a return to “intense fighting” if hostages are not freed by Saturday.

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 police said the stores were selling books that supported terrorism, and that two of their owners had been arrested. A brother of the owners decried the raid as “political persecution.”

During the war with Hamas, troops patrolled the Netzarim Corridor, which splits Gaza, preventing evacuated Palestinians from returning north.

A halt in foreign aid may undermine American organizations’ support for forces that guard the two largest camps holding Islamic State members and their families.

President-elect Donald J. Trump said “all hell will break out in the Middle East” if hostages captured in the Hamas-led attacks were not freed before he takes office.