Israel said on Sunday it was delaying the release of more than 600 Palestinians in return for six living and four dead hostages who had been freed, accusing Hamas of repeated violations including “humiliating” handover ceremonies.

A senior Hamas official said the decision exposed the entire agreement to “grave danger” and called on mediators, especially the US, to pressure Israel.

The deal’s first phase and temporary six-week truce is set to expire on Saturday but indirect negotiations on the second phase and an end to the war have not yet begun.

UN Secretary General António Guterres warned that the ceasefire was “precarious” and that a resumption of hostilities must be avoided at all costs.

He also called for the “dignified release of all remaining hostages”.

On Saturday – the start of the sixth and final week of the ceasefire deal’s first phase – Hamas released six living Israeli hostages.

As with many of the previous handovers, five of them were led onto stages beside armed fighters before being transferred to the Red Cross and then taken to Israel.

Later, Hamas posted a video of two other hostages in a vehicle watching one of the handover ceremonies and appearing to plead with Israeli Prime Minister Benjamin Netanyahu to get them out too. A forum representing the hostages’ families condemned the video as a “sickening display of cruelty”.

There was already fury in Israel after Hamas returned the bodies of four hostages earlier in the week, including those of Shiri Bibas and her two young sons Ariel and Kfir, who were abducted during the 7 October 2023 attacks on Israel.

It emerged on Friday that Hamas had handed over the remains of a Palestinian woman rather than those of Ms Bibas. The group said there had been a mistake and transferred Ms Bibas’s body later that day.

Israeli authorities also said a post-mortem had shown that Ariel and Kfir’s captors killed the boys “with their bare hands”, contradicting Hamas’s claim that they died in an Israeli air strike.

Israel was scheduled to free 620 Palestinian prisoners in exchange for the 10 hostages. More than 400 were Gazans detained by Israeli forces during the war, while 50 of the prisoners were serving life sentences in Israeli jails.

They had reportedly already boarded buses at a prison in the occupied West Bank when the order came to suspend their release while Netanyahu consulted ministers.

In the early hours of Sunday, the prime minister’s office said the release would be postponed “in light of Hamas’s repeated violations, including the ceremonies that humiliate our hostages and the cynical exploitation of our hostages for propaganda purposes”.

“It has been decided to delay the release of terrorists that was planned for yesterday until the release of the next hostages has been assured, and without the humiliating ceremonies.”

Hamas – which is proscribed as a terrorist organisation by Israel, the US, UK and other countries – denounced Israel’s decision as a “blatant violation” of the deal and warned US, Qatari and Egyptian mediators that there could be no talks on extending the ceasefire until the prisoners were released.

“We have conveyed a clear and strong message to the mediators – we cannot continue discussing any further steps if these 620 Palestinians are not released,” Hamas political bureau member Basem Naim said in an interview with Al Jazeera on Monday.

Asked if the scheduled release of the bodies of another four Israeli hostages on Thursday could be affected, he replied that “all options are on the table”.

“Before going to the next step, we have to be sure that the past step [will happen],” he added.

“Netanyahu is clearly sending strong messages that he is intentionally sabotaging the deal, he is preparing the atmosphere for returning back to the war. Therefore, what are the guarantees that he might take the other four bodies and again not release the agreed-upon number of Palestinians, plus the 620 Palestinians?”

Naim said Hamas had discussed Israel’s complaints about the hostage handover ceremonies, but denied they had been humiliating and alleged that Israeli authorities had mistreated Palestinian prisoners before they were released.

The White House backed Israel’s decision to delay the prisoner release, saying it was an “appropriate response” to what it called the “barbaric treatment” of hostages by Hamas.

But President Donald Trump’s Middle East envoy, Steve Witkoff, said he would travel to the region this week with the aim of getting “an extension of phase one”.

“We’re hopeful that we have the proper time… to begin phase two, and finish it off and get more hostages released,” he told CNN on Sunday.

A total of 33 Israeli hostages are supposed to be exchanged for about 1,900 Palestinian prisoners and detainees from Gaza during the ceasefire deal’s first phase.

So far, 25 living hostages and four dead hostages have been released, while the bodies of the last four hostages are scheduled to be handed over this week. Five living Thai hostages have also been freed outside the deal.

The agreement has also seen Israeli forces withdraw from densely populated areas of Gaza. Hundreds of thousands of displaced Palestinians have been allowed to return to their homes in the north and hundreds of aid lorries are now being allowed into the territory each day.

The ceasefire’s second phase should see the remaining hostages released, a full Israeli withdrawal and a permanent ceasefire.

The Israeli military launched a campaign to destroy Hamas in response to an unprecedented cross-border attack on 7 October 2023, in which about 1,200 people were killed and 251 were taken hostage.

At least 48,346 people have been killed in Gaza since then, according to the territory’s Hamas-run health ministry.

Most of Gaza’s population has also been displaced multiple times, almost 70% of buildings are estimated to be damaged or destroyed, the healthcare, water, sanitation and hygiene systems have collapsed, and there are shortages of food, fuel, medicine and shelter.

The Israel Defense Forces (IDF) said the reservist, who it did not name, was convicted over “several incidents in which he punched the detainees with his fists and used his weapon while they were handcuffed and blindfolded”.

“These acts were committed in the presence of other soldiers, some of whom called on him to stop, and were even documented on the defendant’s mobile phone,” it added.

The Haaretz newspaper said he was the first soldier convicted of abusing Gazans held during the war with Hamas.

He had made the Palestinians say demeaning phrases and make animal noises, and beat them while they were bound and blindfolded, Haaretz reported.

It also cited the Beit Lid Military Court as saying the soldier admitted to three counts of aggravated abuse and one count of unbecoming conduct as part of a plea deal with prosecutors.

They related to four separate incidents between January and June 2024, when he was guarding lorries transporting detainees, it said.

According to Haaretz, the court found an unspecified number of masked soldiers, whose identities remain unknown, had also participated in the abuse.

In addition to the prison term, the convicted soldier was also given a suspended sentence and demoted to the rank of private, according to the IDF.

“Soldiers have a duty to use the force entrusted to them in accordance with IDF values and orders, at all times and in times of war in particular,” the IDF said.

The Sde Teiman detention facility was set up after the start of the Gaza war 15 months ago. Since then, it has been at the centre of reports of serious abuses.

In July, far-right protesters broke into Sde Teiman after Israeli military police went there to question nine reservists suspected of raping a detainee and causing a life-threatening injury to him. Several of the reservists were subsequently arrested.

In October, a report by a UN commission of inquiry alleged that thousands of child and adult detainees from Gaza had been “subjected to widespread and systematic abuse, physical and psychological violence, and sexual and gender-based violence amounting to the war crime and crime against humanity of torture and the war crime of rape and other forms of sexual violence”.

Israel’s government said it rejected the accusations of widespread ill-treatment and torture of detainees, and insisted that it was “fully committed to international legal standards”. It also said it had carried out thorough investigations into every complaint.

The Israeli military launched a campaign to destroy Hamas in response to an unprecedented cross-border attack on 7 October 2023, in which about 1,200 people were killed and 251 were taken hostage.

More than 47,550 people have been killed in Gaza since then, according to the territory’s Hamas-run health ministry.

According to the Israeli rights group HaMoked, 1,802 Palestinians from Gaza are currently being held as “unlawful combatants” in Israeli prisons. The figure does not include detainees being held by the military.

Yarden Bibas, 34, Ofer Kalderon, 53, and Keith Siegel, 65, were handed over to the Red Cross – the latest hostages to be released as part of a ceasefire deal struck last month.

Palestinian prisoners were taken in buses to Gaza and the West Bank, many of them coming from the nearby Ofer prison.

The tone of the exchange sat in stark contrast to Thursday’s chaotic handover, during which surging crowds pressed in on hostages, eliciting concern for their safety and prompting Israel to delay that day’s release of Palestinian prisoners.

Saturday’s release was more orderly, but retained the presentational elements that sought to project that Hamas remains the governing force in Gaza.

Lines of armed fighters kept crowds at bay, while the men who were released were flanked by more armed and masked fighters. A banner behind them bore the images of killed Hamas leaders.

Officials from the Red Cross signed certificates of release for Mr Kalderon and Mr Bibas, who were then made to hold them as they waved to the crowd in Khan Younis.

As Mr Siegel, a US-Israeli dual national, appeared on stage in Gaza City, a crowd gathered in Hostages Square in Tel Aviv erupted into cheers, some chanting: “He’s a hero, he’s a hero.” One woman described feeling “pure happiness”.

Mr Siegel’s wife, Adrienne, said “there’s no one happier than me” as she was filmed getting into a car to go and meet her husband.

The family of French-Israeli Mr Kalderon said in a statement that they were “overwhelmed with joy, relief, and emotion after 484 long and difficult days of unbearable waiting”.

They added that he “endured months in a nightmare”, holding onto the “hope of embracing his children again”.

But others, like Liz Domsky, had mixed feelings.

“They all need to come home,” she said while watching the proceedings from Hostages Square.

“I have a student there, Bar Kupershtein. I was a teacher in the high school where he studied. We are very worried about him. We hope he’ll come back. He’s not in the first list.”

There was a similar complexity of emotion in Israel over the release of Mr Bibas, whose wife, Shiri, and two young sons, Ariel and Kfir, were also kidnapped during the 7 October 2023 attack by Hamas.

Hamas claimed that they had been killed by an Israeli air strike early on in the ensuing war – but they were named in a list of hostages it said in January it was willing to free.

Holding up an image of Kfir, who was just nine months old when he was taken, Andrea Wittenberg remarked: “They are children. They should be at home. It is impossible for them to be in Gaza.”

She added: “I don’t want to give up.”

Israeli President Isaac Herzog described Mr Bibas’s return as “simply heartbreaking”, saying his country remained “deeply concerned” about their fate. “As an entire nation we hold them in our hearts,” he wrote.

Herzog added that each released hostage “deserves the time to rehabilitate and rebuild their lives, and every one of the hostages deserves to come home soon”.

0:50Celebrations as crowd greets freed Palestinian prisoners in West Bank

In Ramallah, in the occupied West Bank, buses of freed Palestinian prisoners were met by large and jubilant crowds.

“Today we were born again…we left the narrowness of the graves to the spaciousness of the world,” Nasrallah Muammar, who was released after 17 years in prison, said in his first statement, according to Palestinian media.

“I feel joy despite the journey of pain and hardship that we lived,” Ali Al-Barghouti, who was serving two life sentences, told Reuters.

Saturday’s hostage release was more organised than the one on Thursday, when two Israelis and five Thai nationals were led through cheering crowds, who at times had to be pushed out of the way.

Described as “shocking scenes” by Israeli Prime Minister Benjamin Netanyahu, Israel demanded – and received assurances – that they would not be repeated.

International Committee of the Red Cross President Mirjana Spoljaric had urged that security around the handovers be improved and they “take place in a safe and dignified manner”.

According to the Hamas-run Gaza health ministry, nearly 47,500 people have been killed in the territory since Israel invaded in the wake of the 7 October 2023 attack, in which around 1,200 Israelis were killed and 251 taken hostage.

A ceasefire and hostage release agreement between Israel and Hamas began on 19 January, with the first stage to see 33 hostages and 1,900 prisoners released, as well as hundreds of lorries carrying humanitarian aid being allowed into Gaza each day.

• What we know about the deal

The Rafah crossing between Gaza and Egypt – a key humanitarian corridor – was also reopened on Saturday, after eight months of being closed.

The Gaza health ministry said 50 patients had left via the crossing to access medical care in Egypt.

Hundreds of thousands of displaced Palestinians have also been allowed to return to their homes in northern Gaza this week.

But Ashraf al-Dous, among them, said that some, including his father, have gone back to the south after seeing the scale of the destruction caused by Israeli air strikes.

“It really a mess,” he said. “The situation is catastrophic.”

Most of the floors in his apartment building in northern Gaza City have been destroyed, he said. “I didn’t expect the situation to be like this – it’s too much.”

Among those released and tasting freedom for the first time in 22 years was 47-year-old Hussain Nassar, who was arrested in 2003 for taking part in the second Palestinian Intifada, or uprising.

There to meet him were his daughters, 22-old Hedaya and Raghad, who’s 21. Both were dressed in the striking traditional red and black dresses from Nablus, their hometown.

The younger daughter had earlier told me that it was impossible to describe living for so long without her dad.

“This is the first time I will touch him. I will hug him. I cannot express my feelings.”

Almost shaking with the excitement of meeting her father, she said “the Israelis arrested him when my mum was pregnant with me. I feel like this is the first time I will know what it’s like to have a father!”

Among the 110 Palestinian prisoners released at this stage of what is still a fragile ceasefire, were several women and children – the youngest of them 15 years old.

Some of them were accused of relatively minor offences, others had not been convicted or formally charged.

But 21 prisoners convicted of the most serious offences, including murder, were not allowed by Israel to return home to the Palestinian Territories and were exiled to Egypt or neighbouring countries.

One senior figure who was not sent into exile, despite being convicted for his involvement in the deaths of several Israelis, was Zakaria Zubeidi.

The former commander in the al-Aqsa Martyrs’ Brigades was one of several detainees carried aloft by jubilant supporters through the streets near Ramallah’s civic centre.

It was a scene, like the earlier Hamas show of strength in Gaza, that will irk many Israelis and undoubtedly lead to renewed calls from some right-wing politicians for the war against Hamas in Gaza to resume after this initial six-week phase of the ceasefire is over.

For the governor of Ramallah and El Bireh, Dr Leila Abu Ghanam, this homecoming for so many former prisoners was an occasion to celebrate.

But she had mixed emotions as Israeli military operations intensify in the northern part of the occupied West Bank, and the Gaza ceasefire is still under strain.

“All Palestinians are happy about the release of the prisoners but we’re sad about what is happening in the provinces at this very moment. Mothers today, despite how happy they are for the release of their children, are also sad for those mothers who have lost their homes and children.”

Today was one of very few days, while covering this intractable conflict, that I’ve seen so many happy faces among both Palestinians and Israelis.

It has been a terrible, destructive war that has shattered so many lives.

Governor Ghanam accused the Israeli government of not being interested in peace. “But we don’t lose hope,” she said, smiling. “If we had lost hope, Palestinians would have ended 75 years ago.”

The next batch of prisoner releases in exchange for Israeli hostages should happen on Saturday.