The Israeli military said on Friday that one of the bodies released by Hamas did not belong to any of the hostages held in Gaza, accusing Hamas of violating an already shaking ceasefire.
Two of the bodies were identified as infant Kfir Bibas and his four-year-old brother Ariel, while a third body that was supposed to be their mother, Shiri, was found not to match with any hostage and remained unidentified, the military said.
"This is a violation of utmost severity by the Hamas terrorist organization, which is obliged under the agreement to return four deceased hostages," the military said, in a statement, demanding the return of Shiri and all hostages.
The family of hostage Oded Lifshitz, said in a statement that his body had been formally identified.
There was no immediate reaction from Hamas.
Israeli Prime Minister Benjamin Netanyahu earlier vowed revenge on Hamas after the group released the remains of what it said were four hostages, including that of Kfir and Ariel, the youngest of those abducted during the October 7, 2023, attack.
Palestinian militants handed over four black coffins in a carefully orchestrated public display as a crowd of Palestinians and dozens of armed Hamas militants watched, creating a spectacle which was condemned by UN Secretary-General Antonio Guterres. The purported remains of the boys, their mother and Lifshitz, were handed over under the Gaza ceasefire agreement reached last month with the backing of the United States and the mediation of Qatar and Egypt.
In a recorded address released after the remains of the hostages were handed over, Netanyahu vowed to eliminate Hamas, saying "the four coffins" obliged Israel to ensure "more than ever" that there was no repeat of the October 7 attack.
Kfir Bibas was nine months old when the Bibas family, including their father Yarden, was abducted at Kibbutz Nir Oz, one of a string of communities near Gaza that were overrun by Hamas-led attackers from Gaza.
Hamas said in November 2023 that the boys and their mother had been killed in an Israeli airstrike, but their deaths were not confirmed by Israeli authorities.
"Shiri and the kids became a symbol," said Yiftach Cohen, of the Nir Oz kibbutz, which lost around a quarter of its residents, either killed or kidnapped, during the assault.
Yarden Bibas was returned alive in an exchange for prisoners this month.
Lifshitz was 83 when he was abducted from Nir Oz, the kibbutz he helped found. His wife, Yocheved, 85 at the time, was seized with him and released two weeks later, along with another woman.
The handover marked the first return of dead bodies during the current agreement.
The military said that the Bibas children had been murdered in captivity in November 2023 by "terrorists". The prime minister's office earlier said that Lifshitz was murdered in captivity by Islamic Jihad, another militant group in Gaza.
Chen Kugel, the head of the Israel National Center of Forensic Medicine, later said in a televised statement that Lifshitz had been murdered more than a year ago.
