Israel has confirmed the identities of three deceased hostages whose bodies it received from Hamas via the Red Cross in Gaza on Sunday.

Forensic tests showed the remains were those of Israeli soldiers Col Asaf Hamami, 40, Capt Omer Neutra, 21, and Staff Sgt Oz Daniel, 19, the prime minister’s office said.

The confirmation means eight dead Israeli and foreign hostages are still in Gaza.

Under the first phase of the US-brokered ceasefire deal with Israel that started more than three weeks ago, Hamas agreed to return all 20 living and 28 dead hostages it was holding.

Israel has accused Hamas of deliberately delaying the recovery of the dead hostages’ bodies, while Hamas has insisted it is struggling to find them under rubble.

The slow progress has meant there has been no advance on any of the substantive issues in the second phase of the ceasefire deal, including plans for the governance of Gaza, the withdrawal of Israeli troops, the disarmament of Hamas, and how to organise the reconstruction of a territory left devastated by two years of war.

Hamas’s armed wing, the al-Qassam Brigades, handed over the remains of the three hostages to the Red Cross on Sunday night after saying they had been found “along the route of one of the tunnels in the southern Gaza Strip”.

The bodies were transferred to Israeli forces in Gaza before being transported to the National Centre of Forensic Medicine in Tel Aviv for identification.

On Monday morning, the Israeli prime minister’s office announced that the remains belonged to Col Hamami, Capt Neutra and Staff Sgt Daniel.

“The government of Israel shares in the deep sorrow of the Hamami, Neutra and Daniel families, and all the families of the deceased hostages,” a statement said.

“The Hamas terrorist organisation is required to uphold its commitments to the mediators and return them as part of the implementation of the agreement. We will not compromise on this and will spare no effort until we return all of the hostages, every last one of them,” it added.

Col Hamami was commander of the Southern Brigade of the Israel Defense Forces (IDF) Gaza Division. The IDF said the father-of-three was among the first troops to reach the combat zones following the Hamas-led attack on southern Israel on 7 October 2023 and was “the first to declare war”. He was killed fighting near Kibbutz Nirim and his body was then taken to Gaza by Hamas as a hostage, it added.

Capt Neutra, an Israeli-American dual national who was born in the US and emigrated to Israel, was serving as a platoon commander in the IDF’s 7th Brigade. The IDF said he was killed in battle near the Gaza perimeter and that his body was abducted by Hamas.

Staff Sgt Daniel was serving in the IDF’s 7th Armoured Brigade. He was also killed during a battle with Hamas gunmen near the Gaza perimeter and his body was taken by them as a hostage, according to the IDF.

The Hostages and Missing Families Forum in Israel, which represents many hostages’ relatives, said it “bows its head in sorrow and shares in the profound grief” of the three men’s families.

“There are no words to express the depth of this pain. The hostages have no time. We must bring them all home, now!”

Hamas and Israel have accused each other of repeated violations of the ceasefire since it took effect on 10 October.

On Sunday, an Israeli air strike killed a man in northern Gaza, according to the Hamas-run health ministry.

The Israeli military said it had struck a “terrorist” who had crossed the “Yellow Line”, which demarcates territory in Gaza still under Israeli control, and was posing a threat to its troops.

Under the deal, Hamas agreed to return all the hostages it was holding within 72 hours.

All the living Israeli hostages were released on 13 October in exchange for 250 Palestinian prisoners and 1,718 detainees from Gaza.

Israel has so far handed over the bodies of 225 Palestinians in exchange for the bodies of the 18 Israeli hostages so far returned by Hamas, along with those of two foreign hostages – one of them Thai and the other Nepalese.

Six of the eight dead hostages still in Gaza are Israelis, one is Tanzanian, and one is Thai.

All but one of the dead hostages still in Gaza were among the 251 people abducted during the Hamas-led attack on southern Israel on 7 October 2023, during which about 1,200 other people were killed.

Israel responded by launching a military campaign in Gaza, during which more than 68,800 people have been killed, according to the territory’s health ministry.