LONDON — British police have arrested two teenagers in connection with a weekend arson attack on a synagogue in northwest London, as Jewish leaders express concern about a wave of incidents targeting their community.

Deputy Commissioner Matt Jukes of London’s Metropolitan Police Service on Monday said officers arrested two young men, aged 19 and 17, overnight in relation to the attack on the Kenton United Synagogue in the borough of Harrow. The department has made 15 arrests related to six attacks on Jewish targets and a Persian-language media organization critical of Iran’s government that occurred over the past few weeks, he said in an interview with the BBC.

One “serious line of inquiry” is that Iran is hiring local criminals to carry out these attacks amid tensions in the Middle East, including the U.S.-Israeli war against the Islamic Republic, Jukes said.

“We’ve seen a pattern with other actors of thugs for hire, people taking cash that looks like quick and easy money,” Jukes said. “This is part of the modern hybrid war fought by proxies.”

In the most recent incident, a bottle containing a flammable liquid was thrown through the window of the Harrow synagogue on Saturday night, causing smoke damage, police said.

Counterterrorism police are investigating the series of incidents, which began on March 23 when an arson attack destroyed four ambulances owned by a Jewish charity that serves people of all faiths in north London. Police on Friday closed Kensington Gardens, a central London park visited by thousands of tourists and local residents every day, to investigate an alleged drone attack on the nearby Israeli embassy.

No one has been injured in the incidents, which all happened within a few miles (kilometers) of each other.

Chief Rabbi Ephraim Mirvis said on Sunday that “a sustained campaign of violence and intimidation against the Jewish community of the UK is gathering momentum.”

“Thank God, no lives have been lost, but we cannot, and must not, wait for that to change before we understand just how dangerous this moment is for all of our society,” he said on X.

Deputy Assistant Commissioner Vicki Evans on Sunday said police are aware that a group calling itself Harakat Ashab al-Yamin al-Islamia had claimed responsibility for most of the attacks in Britain. The same group has claimed responsibility for incidents in recent months at places of worship, business and financial institutions across Europe, all of which appear to be linked to Jewish or Israeli interests, she said.

Israel’s government has described Harakat Ashab al-Yamin al-Islamia, whose name means the Islamic Movement of the Companions of the Right, as a recently founded group with suspected links to “an Iranian proxy.”

“I want to be clear, irrespective of the motivation of this group, to those facilitating on their behalf and those committing the acts – we will not tolerate activity which seeks to intimidate or frighten our communities. You will not succeed in creating division and hate,” Evans said.

The U.K. has accused Iran of using criminal proxies to conduct attacks on European soil targeting opposition media outlets and the Jewish community. Britain’s MI5 domestic intelligence service says that more than 20 “potentially lethal” Iran-backed plots were disrupted in the year to October.