Explained | What are the details of the Israel-Hamas hostage deal?

Israel and the Palestinian Islamist group Hamas began a four-day truce on Friday morning, with the first of four daily exchanges of hostages held in Gaza in return for Palestinian prisoners in Israeli jails taking place later each day.

What are the details of the deal?

Under the Israel-Hamas deal, the two sides agreed to a four-day truce so that 50 women, children and teenagers under the age of 19 taken hostage could be freed in return for 150 Palestinian women and teenagers in Israeli detention. The deal includes an agreement to allow more emergency aid and fuel into Gaza.

The hostages, among about 240 taken by Hamas in their Oct. 7 raid on Israel, have been released in groups of a dozen or so each day in exchange for groups of Palestinian prisoners. As of Sunday, 40 Israelis - some of them holding dual citizenship - had been released, according to an Israeli tally. In addition 17 Thai citizens and one Filipino - farm workers employed in southern Israel when they were seized - were freed under a separate agreement.

Those involved in the deal for the Israeli hostages have described the break in hostilities as "a humanitarian pause".

Qatar's chief negotiator in ceasefire talks, Minister of State at the Foreign Ministry Mohammed Al-Khulaifi, said that while the truce was in place there would be "no attack whatsoever. No military movements, no expansion, nothing."

When did the deal start and can it be extended?

The truce began at 7 am (0500 GMT) on Friday. If not extended, it is due to end some time on Tuesday.

The pause can be extended by a day for each additional batch of at least 10 hostages released by Hamas.

An Israeli official would not say when precisely the truce would expire, telling Reuters that "it's a fluid situation".

To secure an extension, the official said that Hamas had to produce a new list of hostages it proposed to release and that this had to be approved by Israel. In return, Israel would free three times the number of Palestinian prisoners.

The official said the exchange process could last for a maximum of four days beyond the four days initially agreed, based on an Israeli calculation that there were 100 women and children held in Gaza. If that took place, the deal could last until Saturday, Dec. 2.

From the start, Israel provided a list of 300 Palestinians it said it was ready to release in return for a total of 100 hostages.

What happens when the truce ends?

According to an Israeli cabinet decision, Israel is committed to resuming its offensive against Hamas in Gaza immediately once the truce expires.

Hamas said when details of the agreement were announced that its "fingers remain on the trigger" throughout the truce.

How is the deal being implemented?

The International Committee of the Red Cross (ICRC) is working in Gaza to facilitate the release of hostages, Qatar said.

Hostages have been transported through the Rafah crossing to Egypt, the only country apart from Israel to share a border with Gaza. In return, Palestinians have been released from Israeli jails and taken to Jerusalem and Ramallah, the West Bank city which is home to the headquarters of the Palestinian Authority.

During the truce, trucks loaded with aid and fuel have crossed into Gaza, where 2.3 million people have been running out of food and many hospitals have shut down in part because they no longer have fuel for their generators.

Qatar said that an operations room in the Qatari capital would monitor the truce and the exchange and that it had direct lines of communication with Israel, the Hamas political office in Doha and the ICRC. Doha has helped iron out glitches, including working to resolve concerns raised by both sides over lists of those being freed.

Who are the hostages being released?

The Israeli hostages released by Hamas have included children, some of their mothers and elderly women.

As well as Israeli civilians and soldiers taken on Oct. 7, more than half the roughly 240 hostages are foreign and dual nationals from about 40 countries including Argentina, Britain, Chile, France, Germany, Portugal, Spain, Thailand and the US, Israel's government has said. US President Joe Biden said on Sunday among those freed was a 4-year-old American hostage.

Not all the hostages taken on Oct. 7 are held by Hamas fighters.

Who are the Palestinians being freed and why were they held?

As part of the exchange, Israel has freed women and teenagers from Israeli jails.

The Palestinian Prisoners Society said before the exchange began that 7,200 Palestinian prisoners were being held by Israel, among them 88 women and 250 children 17 and under.

Most on Israel's list of those to be freed are from the Israeli-occupied West Bank and Jerusalem and were held for incidents such as attempted stabbings, hurling stones at Israeli soldiers, making explosives, damaging property and having contacts with hostile organisations. None are accused of murder.

Many were held under Israeli administrative detention, meaning they were detained without trial.

Who negotiated the deal?

Qatar played a major mediation role. Hamas has a political office in Doha and the Qatari government has kept channels of communication open with Israel, even though unlike some other Gulf Arab states it has not normalised ties with Israel.

The US also played a crucial role, with the US president holding calls with Qatari Emir Sheikh Tamim bin Hamad Al Thani and Israeli Prime Minister Benjamin Netanyahu in the weeks leading up to the deal.

Egypt, the first Arab state to sign a peace deal with Israel and which has long played a mediation role over the decades of the Israeli-Palestinian conflict, has also been involved.

Why has it taken so long to negotiate?

The deal was announced 46 days after the start of the war, one of the most fierce conflicts to erupt between the two sides. Hamas fighters killed 1,200 people when they launched their raid on Israel, the biggest single-day toll on Israeli soil since its creation in 1948. As of Sunday, about 14,800 people in Gaza had been killed in the Israeli offensive, the most by far of any recent war.

Amid such ferocious fighting, the large number of hostages and Israel's stated determination to wipe out Hamas in Gaza, mediating even a temporary deal, like this one, proved far more challenging than in previous conflicts.

The initial negotiations for a deal between Israel and Hamas, both sworn enemies, began within days of the Oct. 7 attack but progress was slow. This was partly because communications had to go via Doha or Cairo on every detail.

In 2014, when Israel last launched a major land invasion in Gaza, it took 49 days for both sides to implement a ceasefire deal, but that ended major fighting for several years.