Israeli forces were withdrawing from a key Gaza corridor on Sunday, Israeli officials and Hamas said, part of Israel's commitments under a tenuous ceasefire deal with Hamas that is moving ahead but faces a major test over whether the sides can negotiate its planned extension.

Hamas released three Israeli civilian men it held hostage in Gaza for the past 16 months, and Israel freed 183 Palestinian prisoners as the tenuous Gaza ceasefire ends its third week.

It is believed that at least two of the six American hostages still held in Gaza are alive — Sagui Dekel-Chen, 35, who grew up in Bloomfield, Connecticut, and Edan Alexander, 19, from Tenafly, New Jersey. Four other Americans are believed to have been killed in captivity.