The use of proxies by hostile states to carry out attacks in the UK is a "growing concern", the prime minister has said.

Sir Keir Starmer expressed worry over the use of proxies - groups used by states to carry out criminal acts - by "a number of countries" during a visit to Kenton United Synagogue, which was targeted with a petrol bomb on Saturday.

There has been a series of arson attacks against targets belonging to the Jewish community in the UK since late March, including two synagogues and a former Jewish charity.

An Islamist group suspected of having Iranian links - Harakat Ashab al-Yamin al-Islamia - claimed responsibility for an attack on Jewish community ambulances in north London, along with other incidents in the UK and Europe.

Sir Keir met Chief Rabbi Sir Ephraim Mirvis and other members of the community at Kenton United Synagogue in north-west London on Thursday.

Before the meeting, Saul Taylor, the president of the United Synagogue, an umbrella group which includes the one visited by the prime minister, said there was a lot of anger in the Jewish community with the government.

"There's been so much that's been dragging," he said, urging the government to proscribe Iran's Islamic Revolutionary Guard Corps (IRGC).

"I don't know what they're waiting for."

He said synagogues were spending enormous amounts of money on security guards, saying one spends £20,000 a month.

He called it a "tax on being Jewish in Britain".

Sir Keir said "the use of proxies in this country is a growing concern and a real concern", and the UK must "deal with malign state actors".

"It's very important this particular context, because I'm increasingly concerned that a number of countries are using proxies for attacks in this country."

He said the government would bring forward legislation "as quickly as possible" to proscribe the IRGC. Other European countries have already done so.

Before the 2024 general election Labour had promised to proscribe it and has faced criticism that it has not yet happened. Other groups like the Iran-backed Hezbollah have been proscribed.

Last year, the government's independent reviewer of terror legislation said new laws were needed to tackle state-run organisations.

Sir Keir told those gathered: "I've come here to stand with you."

"The Britain that I want is a Britain where people can practice their religion, their faith, in safety and security.

"That's amongst the reasons I wanted to come here personally myself this afternoon to hear first hand from the people affected by the attack this weekend."

The chief rabbi, who said the Jewish community was filled with anxiety after the attacks, said he had asked Sir Keir to "guarantee the normalisation of antisemitism in the UK will stop, and that there will be zero tolerance".

Sir Ephraim also urged the prime minister to proscribe the IRGC and "all other terrorist organisations, whether state sponsored or not".

Police are continuing to investigate a series of attacks against the Jewish community.

A 17-year-old boy pleaded guilty to arson not endangering life at Kenton United Synagogue. Another teenager was arrested and released on bail, and the police are still looking for two other suspects.

The boy, a British national from Brent, was the first to be convicted over a spate of attacks against Jewish buildings and a dissident Persian media company.

He climbed over the synagogue wall, smashed a window and threw in a petrol bomb, causing smoke damage to an inside room.

Metropolitan Police Commissioner Sir Mark Rowley told the BBC on Tuesday there had been "a determined and intimidatory series of attacks" against British Jews.

"The whole of society should be as outraged at that as we would be on attacks on any other group because of their race or faith."