by Crowds have gathered for a vigil outside Downing Street in support of victims of the Hamas attacks on Israel.
Some held up pictures of those taken hostage or killed, some lit candles and some stood in tears.
Rishi Sunak joined prayers at a north London synagogue, where he told the British Jewish community he would “stop at nothing to keep you safe”.
Meanwhile, three arrests were made as a pro-Palestinian demonstration took place near the Israeli embassy.
About 900 people have died in Israel since Saturday’s surprise attack, while retaliatory strikes on Gaza have killed almost 690.
Civilians have been taken hostage and the armed wing of Hamas has threatened to kill them if Palestinian civilians are not warned about impending air strikes.
More than 10 Britons are feared dead or missing following the attacks including Nathanel Young and Bernard Cowan.
Most of those taking part in the Downing Street vigil will have relatives or friends affected by the Hamas attacks, with Chief Rabbi Sir Ephraim Mirvis saying there was hardly a Jewish family in the UK not affected.
Rabbi Ephraim told the vigil British Jews were “at one” with the people of Israel and that they stood “shoulder to shoulder with you at this time”.
He said he prayed that “the darkness we are enduring will lead to light. That the chaos, confusion and bitterness, the mourning and the grief, will be replaced by peace.”
Israel’s ambassador to the UK, Tzipi Hotovely, told the crowds it was “so clear that it is a fight between good and evil” and that “good will prevail”.
One Israeli who attended the candle-lit vigil was Hanna Wine, who was supposed to be back in Israel on Monday.
“I’m currently stuck here. My flight got cancelled. I have a close friend who’s missing, she’s probably been taken into Gaza, I don’t know what’s happening to her.
“I don’t think anyone here gets how bad the situation is there. Every single person I know, every boy I know has been drafted. People have been murdered in cold blood.”
Later in the evening, Mr Sunak spoke at Finchley United Synagogue.
“I wanted to come here tonight to stand with you, to stand with you in this hour of grief as we mourn the victims of an utterly abhorrent act of terror, to stand with you in this hour of prayer, as we think of those held hostage and your friends and loved ones taking refuge in bomb shelters, or risking their lives on the frontline,” he said.
“And perhaps above all, I wanted to come here tonight to stand with you in solidarity in Israel’s hour of need.”
Later, in a joint statement, Rishi Sunak, US President Joe Biden, French President Emmanuel Macron, German Chancellor Olaf Scholz and Italian Prime Minister Giorgia Meloni promised their “steadfast and united support to the state of Israel” and their “unequivocal condemnation of Hamas and its appalling acts of 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 said.
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”.
A pro-Palestinian demonstration took place near the Israeli embassy in west London, with thousands gathered – including from groups Stop the War and the Palestine Solidarity Campaign – and chants including “Free Palestine” ringing out.
Large groups of police officers watched on as flares were lit and placards calling for Israel to “end the occupation” were waved.
A 15-year-old male was arrested on Kensington High Street on suspicion of assaulting an emergency worker, while a 70-year-old man was arrested in the Kensington area on suspicion of racially motivated criminal damage, police said.
A 29-year-old man was also arrested in Oxford Street on suspicion on causing actual bodily harm and possession of an offensive weapon, police added.
In response to the attacks by Hamas, Israel has ordered a “complete siege” of the Gaza Strip, cutting off food, fuel, electricity and water supplies.
Home Secretary Suella Braverman has written to police chiefs in England and Wales urging them to step up patrols and use their powers to prevent “disorder and distress to our communities”.
“There is no place for demonstrations, convoys, or flag-waving on British streets that glorifies terrorism or harasses the Jewish community,” she said.
