BBCFirefighters are tackling a suspected arson incident in the north London suburb of Golders Green, the London Fire Brigade (LFB) has said.
Police and fire crew were on the scene with more details expected to come, the LFB told the BBC.
One local resident told the BBC at the scene that he had heard an "explosion" shortly after 01:30 GMT and that "four ambulances" were on fire.
"We've all been woken up... by arsonists targeting the ambulances in our community", they said.
The area is home to Hatzolah, a large non-profit, volunteer organisation that provides Jewish people emergency medical response and transportation to hospitals for free.
It has served the North London community of Golders Green, which has a large Jewish population, since 1979.
The BBC has contacted Hatzolah for comment.
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