The U.S. has brokered a deal between Israel and Hamas to free dozens of hostages held in Gaza in exchange for a four or five day pause in fighting, according to two current U.S. officials and a former U.S. official with knowledge of the talks.

All officials stressed that a deal isn’t final until it’s officially announced and that arrangements can always fall apart at the last moment. They said an announcement could come from the relevant parties as soon as Tuesday.

Elements of the deal, including the release of 50 hostages by Hamas, could begin within hours, they said. The two U.S. officials added that about 150 Palestinian prisoners will also be released from Israel as part of the arrangement.