Israel's national security adviser said the release of hostages under a temporary truce agreement with Gaza's Hamas rulers will not happen before Friday.
"Negotiations for the release of our captives are progressing and continue all the time," Israeli National Security Adviser Tzachi Hanegbi said in a statement released by the prime minister's office.
"The start of the release will proceed according to the original agreement between the parties, and not before Friday," Hanegbi said.
He did not mention any change to the truce agreed with Hamas and approved by Israel's cabinet early Wednesday, which an Israeli official earlier told AFP would go into effect from 10am on Thursday.
Under the deal, Israel and Hamas agreed on a four-day truce in the Gaza war during which the Palestinian militants would free at least 50 of the hostages taken in 7 October attack.
In turn, Israel would release at least 150 Palestinian prisoners and allow more humanitarian aid into the coastal territory after more than six weeks of bombardment, heavy fighting and a crippling siege.
The hostages to be freed in the process are women and children, and the Palestinian prisoners are women and male detainees aged 18 and younger.
The first truce in a brutal, near seven-week-old war, reached after mediation by Qatar, was hailed around the world as a sign of progress that could ease the suffering of civilians in Israeli-besieged Gaza and bring more Israeli captives home.
Israel said the ceasefire could be extended further if more hostages were freed and a Palestinian source said as many as 100 hostages in total could be released by the end of the month.
Hamas and allied groups captured around 240 hostages when Islamist gunmen rampaged through southern Israeli towns last month.
Among those believed to be held by Hamas is nine-year-old Irish-Israeli girl Emily Hand.
Speaking in the Dáil this afternoon, Taoiseach Leo Varadkar said the Government hoped that Emily will be included in those released in the coming days.
Hamas has released four hostages - all women - since 7 October.
The truce was not expected to begin until tomorrow morning, and the start time had yet to be officially announced as of this afternoon.
"The starting time of the pause will be announced within the next 24 hours and last for four days, subject to extension," Qatar's foreign ministry said.
A statement by Israeli Prime Minister Benjamin Netanyahu's office last night said 50 women and children would be released over four days at a rate of at least ten daily.
Beyond that, the truce could be extended day by day as long as an additional ten hostages were freed per day.
Israel's justice ministry published a list of 300 names of Palestinian prisoners who could be freed.
"Israel's government is committed to return all the hostages home. Tonight, it approved the proposed deal as a first stage to achieving this goal," said the government statement.
Hamas said the initial 50 hostages would be released in exchange for 150 Palestinian women and children imprisoned in Israel.
Hundreds of trucks of humanitarian, medical and fuel supplies would enter Gaza, while Israel would halt all air sorties over southern Gaza and maintain a daily six-hour daytime no-fly window in the north, the enclave's ruling Islamists said.
Israel has subjected Gaza to siege and relentless bombardment since the Hamas attack, which killed 1,200 people, mostly civilians, according to Israeli tallies.
Since then, more than 14,000 Gazans have been killed, around 40% of them children, according to medical officials in the territory.
Qatar's chief negotiator in ceasefire talks, minister of state at the foreign ministry Mohammed Al-Khulaifi, told Reuters the truce meant there would be "no attack whatsoever. No military movements, no expansion, nothing".
Qatar hopes the deal "will be a seed to a bigger agreement and a permanent cease of fire...That's our intention," he said.
Pending the start of the truce there was no let-up in fighting. As morning broke, smoke from explosions rose above northern Gaza in live Reuters video from across the border fence.
Riyad al-Maliki, foreign minister in the Palestinian Authority government based in the West Bank, said an entire extended family had been killed today in Jabalia on Gaza's northern edge.
"Only this morning, from the Qadoura family in Jabalia, 52 people have been wiped out completely, killed," he said. "I have the list of the names, 52 of them, they were wiped out completely from grandfather to grandchildren," he said.
Israel's military released footage of soldiers shooting in narrow alleyways and said it had carried out air strikes.
Its "forces continue to operate within the (Gaza) Strip's territory to destroy terrorist infrastructure, eliminate terrorists and locate weaponry", it said.
An Egyptian security source said mediators sought a start time of 10am tomorrow for the truce, though this was still awaiting confirmation from the Israelis, with Hamas seeking a few hours from the start to begin freeing hostages.
A spokesperson for Israel's Defence Ministry said the truce would likely take hold "sometime tomorrow".
'What truce can there be?'
The truce deal is a first small step towards peace in the most violent ruction of the 75-year-old Palestinian-Israeli conflict.
The past seven weeks have shocked the world because of the suffering of civilians on both sides, beginning with the killing of Israeli families in their homes and continuing with destruction rained down on Gaza, home to 2.3 million people.
"What truce can there be after what happened to us? We are all are dead people," said Mona, a woman in Gaza whose nieces and nephews were among those killed by an Israeli air strike that hit the home of the Seyam family.
"This will not bring back what we lost, will not heal our hearts or make up for the tears we shed," she said.
US President Joe Biden was among international leaders who welcomed the deal.
Three Americans, including a three-year-old girl whose parents were killed on 7 October, are expected to be among the hostages to be released, a senior US official said.
Saudi Foreign Minister Prince Faisal bin Farhan Al Saud said the agreed expansion of access for humanitarian aid should become permanent: "Whatever humanitarian access now increases as a result of this hostage deal must remain in place and must be built upon."
UN Secretary-General Antonio Guterres welcomed the agreement as "an important step in the right direction, but much more needs to be done to end the suffering".
Both Israel and Hamas, however, said the pause in hostilities would not halt their broader missions.
"We are at war and we will continue the war until we achieve all our goals. To destroy Hamas, return all our hostages and ensure that no entity in Gaza can threaten Israel," Mr Netanyahu said in a recorded message.
Hamas said in its statement: "As we announce the striking of a truce agreement, we affirm that our fingers remain on the trigger, and our victorious fighters will remain on the look-out to defend our people and defeat the occupation."
Meanwhile, the Israeli military has said it intercepted a cruise missile fired towards the south of the country.
After reports of "an infiltration by a hostile aircraft" near the southern Red Sea resort of Eilat, an Israeli fighter jet "successfully intercepted a cruise missile that was launched toward Israel", it said in a statement.
"No infiltration into Israeli territory was identified," the military added.
Yemen's Huthi rebels, who have declared themselves part of the "axis of resistance" of Iran's allies and proxies, have fired a series of drones and missiles towards Israel since the Gaza war erupted on October 7 when Hamas militants carried out the worst attack in Israel's 75-year history.
