A ninth person has been arrested in connection with an arson attack on Jewish community ambulances in north-west London, police say.

The 48-year-old man was arrested on suspicion of conspiracy to commit arson and taken into custody on Thursday in Leytonstone, north-east London, the Metropolitan Police said.

Four vehicles operated by the charity Hatzola were set alight in Golders Green, causing explosions, in the early hours of the morning on 23 March.

The incident caused about ยฃ1m of damage to the ambulances and the medical equipment they contained, with nearby flats and a synagogue also affected. Prosecutors have said they believe it was a targeted attack against the Jewish community.

Three men and a teenager have previously appeared in court accused of destroying the ambulances. They have been remanded in custody until a plea hearing on 28 August.

"The attack on the Hatzola ambulances caused considerable community concern and we have been working continuously to investigate this incident," Cdr Helen Flanagan, head of Counter Terrorism Police London, said.

"Our aim is to arrest and charge all those responsible for the arson attacks and other incidents targeted at Jewish, Israeli and Iranian sites in recent weeks."

The latest arrest follows a number of separate attacks across London in recent months, including the stabbing of two Jewish men in Golders Green last week.

Thirty-one people had now been arrested as part of various investigations by the Met's counter-terrorism unit into attacks on Jewish sites in London since March, the force said.

These include attacks on two synagogues in north London and a Jewish business.

A 19-year-old man was arrested in Portsmouth on Thursday over an attempted arson attack at the Finchley Reform Synagogue, the Met said. He has been bailed until a date in July.

Investigators have been looking into claims that several of the attacks were carried out on behalf of an Iranian-linked group that has posted videos online about the incidents. They have not ruled out that these may be opportunistic claims.

Last week, the UK's terrorism threat level was lifted from "substantial" to "severe" for the first time in more than four years, following the Golders Green stabbings.

British Jews tell the BBC they are agonising over whether to stick to their usual routine this Sabbath.

Community reflects on the impact of the Golders Green stabbings and security concerns for London's Jews.

Essa Suleiman, 45, is also accused of attempting to murder a third man on the same day in south London.

The Green leader shared a social media post condemning police officers who arrested the suspect in the Golders Green attack.

Chief Rabbi Sir Ephraim Mirvis says there is deep concern and anguish in the Jewish community following the Golders Green attack.