President Trump issued an ultimatum on Monday to Hamas, saying that if all remaining Israeli hostages are not released from Gaza by noon on Saturday, then "all hell is going to break loose." 

Asked by reporters for details on what that meant, Mr. Trump initially responded: "You'll find out, and they'll find out, too. Hamas will find out what I mean." 

He then said ending the ceasefire that took effect on January 19 would be "Israel's decision," but that he felt it would be "appropriate" to cancel the agreement if the hostages aren't released by his deadline. Under the terms of the ceasefire deal negotiated by the U.S., Qatar and Egypt, a total of 33 Israeli hostages were to be released during a six-week first phase, in exchange for the release of about 2,000 Palestinian prisoners from Israeli jails. 

As of Monday, about three weeks into phase-one, about half of the hostages due to be released have thus far been freed, in line with the schedule laid out in the agreement. There are 76 hostages still held by Hamas or its allies in Gaza. On Tuesday, the IDF announced that the oldest one of them, 86-year-old Shlomo Mantzur, had been murdered by Hamas.