Israel and Palestinian militant group Hamas have raised concerns over the lists of Israeli hostages and Palestinian prisoners due to be released on Monday, the final day of an agreed four-day pause in the fighting, an official briefed on the matter said.

The official, speaking on condition of anonymity, told Reuters that Qatari mediators were working with Israel and Hamas to resolve the issues and avoid delays.

Hamas said it wanted to extend the truce. Israel has previously offered to agree to an additional day for each additional 10 hostages freed, and to release three times the number of Palestinian prisoners each time.

"There is a slight issue with today’s lists. The Qataris are working with both sides to resolve it and avoid delays," the official briefed on the matter said.

Israel said earlier it had received overnight what could be the final list of hostages slated for release. The list was being reviewed, Prime Minister Benjamin Netanyahu's office said, adding it would provide further information when possible.

On Sunday, Hamas freed 17 people, including a 4-year-old Israeli-American girl, bringing the total number the militant group has released since Friday to 58. Israel released 39 teenage Palestinian prisoners on Sunday, taking the total number of Palestinians freed since the truce began to 117.

A Palestinian official, familiar with the truce talks, said both Hamas and Israel had shown a positive attitude to requests to extend the four-day truce, but added that "a final decision hasn't yet been reached".

Tuesday in exchange for that becoming an additional truce day. If Israel approves the list, the truce would be extended by a day, with Israel releasing three times the number of Palestinian prisoners as the number of hostages going free.

That process would continue for a maximum of five additional days to the current truce, the official added.

Hamas spokesperson Osama Hamdan, speaking to Lebanon's LBC broadcaster, said the group would try to find more hostages to release and thus prolong the truce. Hamas has previously said it is not holding all the hostages who were brought to Gaza.

The people handed over by Hamas on Sunday included 13 Israelis, three Thais and one with Russian citizenship, and the International Committee of the Red Cross confirmed it had successfully transferred them from Gaza.

'UNTHINKABLE'

U.S. President Joe Biden said he hoped the truce can go on as long as hostages are being released.

Biden said the 4-year-old hostage, Abigail Edan, had witnessed her parents being killed by Hamas fighters during their Oct. 7 rampage into Israel and had been held since then.

"What she endured is unthinkable," Biden said at a news conference in the United States.

Netanyahu, who spoke to Biden at the weekend, said that once the truce ends "we will return with full force to achieve our goals: The elimination of Hamas, ensuring that Gaza does not return to what it was; and of course the release of all our hostages."

The European Union's top diplomat, Josep Borrell, said on Monday the truce was an important first step but that far more would be needed to alleviate the situation and find a way out of the crisis.

Speaking at a Forum for the Union of the Mediterranean in Barcelona, Borrell also urged Israel not to "recolonise Gaza", saying that the creation of a Palestinian state in the West Bank, East Jerusalem and Gaza was the best guarantee of Israel's peace and security.

The four-day truce agreed last week is the first halt in fighting in the seven weeks since Hamas attacked Israel, killing 1,200 people and taking about 240 hostages back into Gaza.

In response to that attack, Israel has bombarded the enclave and mounted a ground offensive in the north. Some 14,800 Palestinians have been killed, Gaza health authorities say, and hundreds of thousands displaced.

Palestinians gave the freed prisoners a jubilant reception in Ramallah, according to Palestinian news agency WAFA.

Omar Abdullah Al Hajj, 17, one of the detainees released on Sunday, told Reuters he'd been kept in the dark about what was happening in the outside world.

"We were 11 people cramped up in a single room where usually there are six. There was never enough food and I was never told how long I was going to stay," he said.

"I can't believe I'm free now but my joy is incomplete because we still have our brothers who remain in prison," said Al Hajj, whom Israel's Justice Ministry accused of belonging to the Islamic Jihad militant group and posing a security threat which it did not specify.

The latest three Thai hostages released were in good health, Thailand's prime minister said. Efforts to free the remaining 15 Thais would continue, the Thai foreign ministry said.

Qatar, Egypt and the United States are pressing for the truce to be extended but it is not clear whether that will happen. Clashes and recriminations have threatened to torpedo the existing deal.

'PEOPLE ARE SO DESPERATE'

Qatari diplomats are now on site in Gaza to supervise the entry and delivery of their country's aid, Qatar's Foreign Ministry said.

A U.N. official who took part in a humanitarian convoy to northern Gaza said on Sunday aid groups were on track to deliver the biggest shipment in over a month, describing thin, gaunt residents slaking their thirst as soon as water arrived.

"People are so desperate and you can see in adults' eyes they haven't eaten," the U.N. children's agency's James Elder told Reuters by video link from southern Gaza after returning from Gaza City.

Even as the aid deliveries flowed north, Elder said he saw hundreds of Gazans heading in the other direction, fearing the renewal of Israeli bombardments if the truce is not prolonged.

"People are so terrified that this pause won't be continued," he said.