Trump hints at 'action' if Hamas doesn't return hostage bodies

President Donald Trump claimed at the peace summit in Egypt that “the war in Gaza is over,” though only the first phase of an agreement has been reached.

“Together we’ve achieved what everybody said was impossible -- at long last, we have peace in the Middle East,” Trump said to the more than 30 world leaders gathered at the summit.

The president said now “the rebuilding begins,” and he said rebuilding may be the “easiest part.”

"All the momentum now is toward a great, glorious and lasting peace, and our commitment to fulfilling the 20-point plan we developed together will be the crucial foundation for achieving that bright future," Trump said. "And it's being worked on right now as we speak, and we're actually in stage three and four."

Phase one has now been agreed upon, and Trump said in earlier remarks in Egypt that phase two of ceasefire negotiations has started.

"Where we can be long advanced on some of the things that we say we're going to do, we can take them out of order in a positive way," Trump explained.

The Red Cross is now in possession of two more coffins of deceased hostages, the Israel Defense Forces and the Israeli Security Agency said.

A total of four bodies of deceased hostages are now on their way to IDF forces.

According to the terms of the first phase of the ceasefire deal, all 20 living hostages and the bodies of all 28 deceased hostages still being held in Gaza were supposed to be returned to Israel on Monday.

Israeli Defense Minister Israel Katz said the return of only four bodies is a “failure to meet commitments” of the first phase of the ceasefire deal, and he said “any delay or deliberate avoidance will be considered a blatant violation of the agreement and will be responded to accordingly.”

President Donald Trump, Egyptian President Abdel Fattah El-Sisi, Turkish President Recep Tayyip Erdoğan and Qatari Emir Tamim bin Hamad Al Thani formally signed the Gaza ceasefire agreement at a ceremony in Egypt on Monday as other world leaders looked on.

“This took 3,000 years to get to this point. Can you believe it? And it's going to hold up too. It's going to hold up,” Trump said.

Before signing the agreement, Trump praised “the richest in the world” gathered around him, saying they “really care for their countries” and credited them for joining forces “to get Gaza straightened out.”

“Why this happened is they all came together and they wanted to get Gaza straightened out. They wanted to get the whole thing straightened out,” Trump said. “It got to a point where it was just crazy. And once they got together and once we started talking, it went really, to me, it went smoothly. It went so smoothly. It was such a big help. But it went so smoothly that nobody could even believe it that we're sitting here and getting this all certified out and all done, and everybody’s happy about it.”

-ABC News' Fritz Farrow

Five of the 20 living hostages who returned to Israel on Monday are being treated at Beilinson Hospital, part of Rabin Medical Center in Israel.

The five hostages -- Evyatar David, Guy Gilboa-Dalal, Alon Ohel, Eitan Mor and Avinatan Or -- are undergoing “comprehensive medical evaluations,” hospital director Dr. Lena Koren said in a statement.

“For each of them, we have assembled a dedicated and personalized medical team, including a physician, mental health professionals, a physiotherapist, and a dietitian," Koren said.

-ABC News Jordana Miller