Rishi Sunak has said he will “stop at nothing” to keep Britain’s Jewish community safe, before promising support for Israel along with other world leaders after the Hamas attacks.
The Prime Minister addressed a synagogue in north London to express his solidarity for Israel and to reassure Britain’s Jews.
“We stand with Israel, the United Kingdom stands with Israel against this terrorism today, tomorrow and always,” Mr Sunak said.
Meanwhile, Home Secretary Suella Braverman wrote to police chiefs to encourage them to step up patrols in areas with large Jewish communities amid concerns they could be subjected to antisemitic abuse.
It comes after Palestinian militant group Hamas sent fighters across the border to Israel and fired thousands of rockets in an unprecedented attack on Saturday.
More than 900 people have been killed in Israel according to the Israeli military with authorities in Gaza saying more than 680 have been killed in the territory, with dozens more taken hostage by Hamas.
Mr Sunak told the United Synagogue in Finchley: “I know that at moments like this, when the Jewish people are under attack in their homeland, Jewish people everywhere can feel less safe.
“We have already seen vile words on our streets and attempts to stir up community tensions.
“I say: Not here. Not in Britain. Not in our country. Not in this century.
“My first duty is to protect you. We will not tolerate this hate, we will not tolerate this antisemitism.
“And I promise you: I will stop at nothing to keep you safe.”
Fireworks were let off, flares were lit and chants of “Israel is a terrorist state”, “Free Palestine” and “Allahu akbar” rang out.
Police separated pro-Israel and pro-Palestinian groups at High Street Kensington tube station.
In Westminster, around 2,000 people attended a Jewish community vigil, arranged by the Board of Deputies of British Jews and the Jewish Leadership Council.
A joint statement by world leaders, including the Prime Minister, said: “We make clear that the terrorist actions of Hamas have no justification, no legitimacy, and must be universally condemned. There is never any justification for terrorism.
“In recent days, the world has watched in horror as Hamas terrorists massacred families in their homes, slaughtered over 200 young people enjoying a music festival, and kidnapped elderly women, children, and entire families, who are now being held as hostages.”
They warned that “this is not a moment for any party hostile to Israel to exploit these attacks to seek advantage”.
The leaders said they recognised the “legitimate aspirations of the Palestinian people”, but “Hamas does not represent those aspirations, and it offers nothing for the Palestinian people other than more terror and bloodshed”.
At least two Britons were killed in the Hamas onslaught, with another feared dead and more missing.
Nathanel Young, 20, was serving in the Israeli army when he was killed in the surprise attack by the group, which began on Saturday.
Bernard Cowan, who grew up around Glasgow, also died.
Jack Marlowe, 26, who went to the same London school as Mr Young, is believed to be missing, while photographer Dan Darlington is feared to be dead.
A post from Mr Darlington’s sister Shelley on social media said that he had been “murdered” at Nir Oz, a kibbutz in southern Israel. However, his death not been officially confirmed.
Mr Marlowe was providing security at a party in the desert near Kibbutz Re’im when the area was attacked by Hamas gunmen.
Foreign Secretary James Cleverly said he was “uncomfortable speculating” on the total numbers of British people affected by the violence after it was reported that more than 10 Britons are feared dead or missing.
He said Israel’s “unique status” meant there were a large number of British-Israeli dual nationals, with Government estimates suggesting about 50,000 to 60,000 Britons are believed to be in either Israel and Gaza.
The Foreign Office has advised against all but essential travel to the region and as flights out of Israel are still available for those wanting to leave there are no plans for a UK-facilitated evacuation of British citizens.
Mr Sunak, who spoke to his Israeli counterpart Benjamin Netanyahu on Sunday, has promised to offer Israel any “diplomatic, intelligence or security” support it needs as it hits back at Hamas.
The US has dispatched an aircraft carrier strike group to the eastern Mediterranean to be ready to assist Israel, and said it will send additional military aid.
Downing Street said the UK is not planning to redeploy military assets to the Middle East, with warship HMS Duncan already in the Mediterranean as part of Nato patrols.
Mr Netanyahu said Israel has “only started” its fierce offensive in the Gaza Strip in response to Hamas’ unprecedented attack.
“What we will do to our enemies in the coming days will reverberate with them for generations,” he said.
Israel sealed the Gaza Strip off from food, fuel, and other supplies in retaliation for the Hamas attack, as the war’s death toll rose to nearly 1,600 on both sides.
Hamas – which is banned as a terrorist group by the UK Government – pledged to kill captured Israeli hostages if attacks targeted civilians in Gaza without warnings.
The most senior Palestinian diplomat in the UK accused Israel of a “war crime” against civilians.
Speaking at a Labour Party conference fringe event in Liverpool he said: “Cutting water and electricity from two million people is a collective punishment. It’s a war crime. It’s not going to lead anywhere.”
The British Red Cross has launched an emergency fundraising appeal to provide humanitarian support in Israel and Gaza.