UK Prime Minister Rishi Sunak has described the situation in Israel as "dangerous and fast-moving", saying that nobody "wants to see any regional escalation".

Sunak tells reporters he's "unequivocal" that Hamas and its supporters are "fully responsible for this appalling act of terror, for the murder of civilians and the kidnapping of innocent people including children".

He says he told Israeli counterpart Benjamin Netanyahu the UK government would do "everything we can to help" and that the country "stands steadfast with Israel, including its right to self-defence".

The PM adds that the UK Foreign Office is in close contact with its Israeli counterpart over the status of British nationals there.

Image source, Downing Street

Nada Tawfik
Reporting from UN headquarters, New York City

Here at the United Nations headquarters in New York, the UN Security Council is about to hold a closed-doors meeting about the Israel-Gaza crisis.

Israel’s ambassador to the UN, Gilad Erdan, spoke to reporters beforehand. He said this unprecedented attack by Hamas was Israel’s 9/11. He held up photos and videos showing bodies strewn on the street and hostages being dragged into vehicles and taken to Gaza.

He said one photo showed a grandmother, who was a Holocaust survivor, in captivity and being forced to hold a rifle.

Erdan said the images would forever be seared in his brain and he demanded that the UN Security Council unequivocally condemn Hamas.

We are also expecting to soon hear from the Palestinian Ambassador to the UN, Riyad Mansour, and will bring you what he says.

Image source, EPA

Bernd Debusmann Jr
Reporting from Washington DC

Image source, Getty Images

More from the United States, which has promised additional support for Israel, as we mentioned earlier.

The US military is deploying naval vessels and combat aircraft to "to bolster regional deterrence efforts" amid the ongoing fighting in Israel, a Pentagon statement says.

Defense Secretary Lloyd Austin says a fleet of vessels centred on a US Navy aircraft carrier has been directed to the eastern Mediterranean. This deployment also includes several guided-missile cruisers and destroyers.

In addition, US Air Force squadrons in the Middle East are being augmented. "The US maintains forces globally to further reinforce this deterrence posture if required," Austin adds.

Extra resources, including munitions, are also being dispatched to Israel, with the first security assistance expected to arrive in the coming days. Austin says the action "underscores the United States’ ironclad support for the Israel Defense Forces and the Israeli people".

The health ministry in Gaza says in its latest update, external that 413 people have been killed, and 2,300 wounded, following retaliatory air strikes from Israel.

The latest official figure we have on the number of Israelis killed is about 600 - although there are reports it's even higher.

In the last hour we've been hearing from BBC reporter Rushdi Abu Alouf, whose live broadcast on the BBC News channel from Gaza was interrupted when a loud explosion was heard.

He spoke to presenter Maryam Moshiri live on air, telling her the explosion sounded "quite close."

Image source, AFP

Pictures have come into the newsroom showing a funeral procession in Rafah, a city in the southern part of the Gaza Strip.

They show a large gathering of mainly men carrying at least 13 bodies wrapped in body bags and white linen. Some are very small - the size of children.

Other pictures show women and a young girl wailing in grief.

Palestinian health ministry officials earlier said at least 313 people, including children, had been killed in Gaza and that another 1,990 had been injured in retaliatory Israeli strikes.

Image source, AFP

Frank Gardner
Security correspondent

Israel is no stranger to hostage crises. As far back as the Entebbe raid in 1976 it showed the world it had the capability and the will to use its special forces to resolve them.

But the current situation in Gaza is on another level altogether. An estimated 100 Israeli citizens are being held by Hamas militants in Gaza after being captured and dragged across the border.

They’re believed to include military officers, civilians, women and children. Hamas are unlikely to concentrate them all in one place.

Instead, they will have been distributed across the heavily populated Gaza Strip, most likely in cellars below ground, their mobile phones and all digital devices taken off them so they’re unable to communicate or reveal their locations.

The Israeli Defense Forces (IDF) have set up a situation room to deal with the issue but any rescue attempt is fraught with danger.

Gaza is so densely inhabited that even a stealthy approach by night is unlikely to go unseen by the intensely hostile population. A potential ground invasion by Israeli troops may release some but endanger others.

And negotiations, if they start, could easily stretch into years.

Bernd Debusmann Jr
Reporting from Washington DC

Image source, Getty Images

US President Joe Biden has "directed additional support" for Israel, according to a White House statement.

The statement says Biden and Vice President Kamala Harris were briefed by their national security team earlier on Sunday about the ongoing clashes in Israel.

"White House officials will remain in close contact with our Israeli partners," the statement adds. "The national security teams are engaged with Israelis and their counterparts throughout the region".

Earlier, US Secretary of State Anthony Blinken made the rounds of talk shows to update US viewers on the fighting and on the US diplomatic response.

Speaking to the BBC's US partner CBS, Blinken said officials were also investigating reports that US citizens had been killed or taken captive by Hamas fighters.

"We can't confirm that in this moment," he said. "But we're very actively working to see if we can confirm the reports that we've had".

In Egypt, the US embassy in Cairo warned Americans to exercise "increased security awareness and precautions" following the shooting death of two Israeli citizens in the city of Alexandria.

Alice Cuddy
Reporting from southern Israel

A dead body lies on the road to Ashkelon.

We can hear rockets overhead, as military vehicles speed past and helicopters circle above us.

On our drive down, we saw two men being held by armed police, partially stripped and blindfolded.

Night is falling here, and people in these southern Israeli communities are still waiting and watching for the potential of an Israeli ground operation into Gaza.

The attacks launched by the Hamas militant group on Saturday marked the biggest escalation in this conflict in decades. Israel launched air strikes in retaliation, and fighting is ongoing inside Israeli territory. Here's the latest:

• Israel says 600 people have been killed since Hamas launched the attacks from Gaza. It says 100 people have been kidnapped and more than 2,000 have been injured
• Some 370 Palestinians have been killed by Israeli strikes, according to the health ministry in Gaza. It says 2,200 people have been injured
• The armed wing of Hamas said this morning it would release the number of Israeli soldiers and civilians it had captured
• US Secretary of State Antony Blinken says there have been reports of US citizens who have been killed. Other countries, including France, Ukraine and Thailand, have also reported deaths
• Two British citizens are missing in Israel - London-born Jake Marlowe and photographer Dan Darlington. Nathanel Young, 20, a British man serving with the Israeli military has been killed
• Police patrols have increased in London after videos emerged of what appears to be people celebrating the attack

The Israeli Defense Forces has just given a short press conference with spokesman Daniel Hagari.

"We will do whatever it takes to protect our people and restore security," he says.

"We are looking to the north as well, with full readiness."

Hagari adds that the IDF believes Hamas militants are hiding amongst Gazan civilians in schools and hospitals.

The media briefing ended abruptly with Hagari saying those "who attack us will face a decisive attack back".

Image source, EPA

Israel's Prime Minister Benjamin Netanyahu has spoken with Ukranian President Volodymyr Zelensky, Germany's Chancellor Olaf Scholz, Italy's Prime Minister Giorgia Meloni and the UK's Prime Minister Rishi Sunak today.

Netanyahu said the leaders he spoke with expressed their full support for Israel to defend itself "as much as it takes".

As we've been reporting, many people are still missing after the attacks on Israel - including some who were at a music festival in the desert, not far from the Gaza border, when militants opened fire.

Family and friends of missing people have since been posting on the festival's social media pages, sharing names and asking: "Have you seen them?"

Among those missing from the festival is 23-year-old American-Israeli Hersh Golberg-Polin. He was there after celebrating his birthday this week, his parents told the Jerusalem Post.

Another man, Moshe Or, told Channel 12 he saw video on social media showing what appeared to be his brother and his brother's girlfriend being taken captive.

"In the video, you see Noa [Argamani] scared, terrified, screaming in panic on a motorcycle... My brother, who is a big guy... is being held by five people," he said.

You can read more here.

Alice Cuddy
Reporting from Israel

I've arrived in Israel after a long journey travelling from the UK.

I landed last night in Istanbul, Turkey, where my flight to Tel Aviv was then delayed by more than nine hours.

I watched as the number of delayed and cancelled flights into Ben Gurion International Airport grew and mulled how to get in.

Meeting with BBC correspondent Anna Foster and her producer Naomi Scherbel-Ball, we moved onto an overnight flight to the Jordanian capital Amman, hoping to make the journey by land.

After waiting for hours at the King Hussein border crossing this morning along with dozens of other people, we were all turned away and told there would be no entry today.

We then headed by car to another crossing in the north of the country, where we were eventually able to pass through.

Staff working at the border spoke of their shock and sadness at what has unfolded this weekend.

Frank Gardner
Security correspondent

In roughly descending order, these will be the Israeli government's immediate priorities:

• Re-establish security in southern Israel. That means eliminating the presence of the remaining Hamas gunmen. Israel will also need to repair and reinforce the punctured border fence between Israel and Gaza
• Destroy or degrade Hamas’s ability to attack Israel. It has never managed to do this. Israel knows that sites destroyed in this weekend’s air strikes can easily be rebuilt. A ground invasion by Israeli troops backed by tanks is one option now, but while this would undoubtedly result in major casualties on both sides it is unlikely to finish off Hamas
• Prevent this conflict from spreading, specifically to the West Bank and Lebanon. If others there were to take up Hamas’s call to arms then Israel would find itself badly overstretched and fighting on three fronts
• Retrieve or rescue the Israeli hostages held by Hamas in Gaza. Israeli Special Forces will have drawn up detailed plans for a potential rescue mission, but the risks are high. Hamas will have almost certainly distributed these men, women and children in several locations, where a rescue team would not be able to approach undetected. Negotiations for their release could take months or even years

Image source, Family handout

A British man serving with the Israeli army has been killed in an attack by Hamas militants, his family says.

Nathanel Young, 20, had been serving with the Israeli Defence Services when he was killed on the Gaza border.

In a statement, his brother Eliot Young said:

Two other British citizens - Jake Marlowe and Dan Darlington - are missing in Israel following Saturday's attacks by Palestinian militants.

You can read more here.

Dr Khamis Elessi, a neuro-rehabilitation and pain medicine consultant based in Gaza City, spoke to the BBC earlier.

"Everywhere you are going in Gaza you see funerals, you see death," he says. "It's like you are watching a movie about the end of life on this earth".

Elessi says he moved his family from their fourth-floor home to his brother's on the ground floor because, on the fourth floor, "the whole building is moving from right to left and from side to side".

He says he hasn't slept since yesterday. "You cannot just close your eyes, the kids are crying and screaming, there is no electricity, there's no internet and so you feel you could be next.

"This bomb could be on top your home, on [on] top of your apartment."

The father of a 23-year-old US citizen has confirmed that his son is among those missing after an outdoor music festival came under attack on Saturday.

California-born Hersh Golberg-Polin, a dual US-Israeli citizen, texted his parents "I love you" and "I'm sorry" while the attack was taking place, his father Jonathan told the Jerusalem Post. , external

Goldberg-Polin had reportedly finished his military service in April and had been working as a waiter and medic since then. He had been living in Israel since he was seven years old.

“We just want him home and safe,” Jonathan Polin told the newspaper.

Yolande Knell
Middle East correspondent, reporting from Ashkelon, southern Israel

Israelis are still processing news of this unprecedented surprise Hamas attack and searching desperately for news of loved ones who are missing.

As the death toll rises, we are seeing shocking footage that shows bodies still lying by roads close to the Gaza Strip. One video shows a dead family’s belongings including a child’s pushchair.

At the main hospital in Ashkelon, we meet a distraught mother, Rachel Ezra, whose son, Oz and his girlfriend, Naomi - aged 24 and 23 - are still missing.

She berates a visiting MP, accusing the government of not doing enough to help. “I want my son,” she shouts, her voice raw. “I don’t know what to say!”

The hospital here has treated over 400 people injured in this huge assault: soldiers from military bases that were overrun, partygoers from a rave in the fields next to Gaza, and locals injured when their homes were hit by rockets.

There are reminders that the fighting still continues with booms overhead as the Iron Dome missile defence system intercepts incoming rocket fire.

Earlier near Ashkelon, motorists filmed the dramatic scenes as Israeli forces engaged in a shootout on a busy road.