One person was killed and four others injured Wednesday after a crane collapsed onto houses in East London, the London Ambulance Service said in a statement.

The 20-meter-high crane fell on two houses and a development of a block of flats in Bow.

Four people were initially found injured at the scene, said the ambulance service, two suffering from head injuries who were taken to hospital.

Subsequently another casualty was discovered.

"Sadly, despite the efforts of emergency services, a fifth person has been found and died at the scene. Our thoughts are with their family at this difficult time," said the ambulance service in a tweet.

It is not known yet what caused the crane to collapse.

AFP