As the Gaza ceasefire takes hold, aid workers caution that the toughest challenges are yet to come, describing the truce as only the first step on a long road to recovery.

The ceasefire came into effect Sunday after an initial three-hour delay, during which almost 20 more Palestinians were killed, according to medics in the decimated Palestinian territory. Under the terms of the deal,

Once the guns fell silent, Palestinians celebrated in the streets of Gaza while Israelis streamed into Tel Aviv’s “Hostages Square” to await their return.

The truce allowed Palestinians to return to bombed-out neighborhoods to begin rebuilding their lives, while relief trucks delivered much-needed aid.

Israel has freed 90 Palestinian prisoners and detainees. The release came early Monday, more than seven hours after three Israeli hostages released from Hamas captivity in Gaza returned to Israel. A large bus carrying dozens of Palestinian detainees exited the gates of Israel’s Ofer prison,

The first three Israeli hostages and 90 Palestinian captives were released Sunday, signs that a long-awaited cease-fire was taking effect in Gaza.

The first three hostages released from Gaza have arrived in Israel, the military announced Sunday, hours after the fragile ceasefire between Israel and Hamas took hold. Their mothers were waiting to meet them.

The three women released are Romi Leshem Gonen, Doron Steinbrecher and Emily Tehila Damari. Per the cease-fire deal, Hamas would release hostages in exchange for Palestinian prisoners held in Israel.