“We are in the process of examining CCTV and are aware of online footage. We believe we are looking for three suspects at this early stage,” superintendent Sarah Jackson said, adding that no arrest has been made.
Nearby homes were evacuated as a precaution while some roads in the area were closed.
London Fire Brigade said the cause of the fire is under investigation.
Shomrim North West London, a charity and volunteer neighbourhood watch group, condemned the arson, branding it a “targeted and deeply concerning incident affecting a vital emergency service serving the local Jewish community”.
“An attack on these ambulances is an attack on the safety, wellbeing, and resilience of our community … There is no place for antisemitism or hate in our society,” the group wrote on Facebook.
Health Secretary West Streeting described the incident as “a sickening attack on Jewish ambulances” and called on anyone with information to share it with police.
Community Security Trust (CST), a charity which monitors antisemitism in the UK, said in a statement on X that it was assisting police in their enquiries.
The ambulances are run by Hatzola, which was established in 1979 and is operated by volunteers.
It provides free medical transportation and emergency response to those living in North London.
The number of antisemitic incidents reported across the UK has soared since the start of the Israel-Hamas War in late 2023, according to CST.
The group recorded 3,700 in 2025, up from 1,662 in 2022.
In October 2025, an attacker drove his car into people gathered outside a Manchester synagogue to celebrate the Jewish holiday of Yom Kippur and stabbed one person to death.
Another person died during the attack after being inadvertently shot by police.