The six Israelis were the last living captives set to be released in the first phase of the cease-fire. The agreement, strained for weeks, has an uncertain future.

Israel has delayed an expected release of hundreds of Palestinian prisoners and detainees in exchange for returned Israeli hostages “until further notice,” the Palestinian Prisoners Society said early Sunday.

Hamas on Saturday released the last six living hostages expected under the first phase of its ceasefire with Israel with a week remaining, as questions over the next phase clouded the deal 's future.