London: A double-decker bus crashed on a tree in central London on Tuesday, killing a woman and injuring nine other people, police said.

It was not immediately clear what caused the bus to crash on the tree on Tower Bridge Road. Police are interrogating the bus driver.

"One woman was pronounced dead at the scene. A further 9 people have been injured and have been taken to central London hospitals," a police statement said.

Paramedics treated a further nine people with minor injuries, a spokesman from the London Ambulance Service said.

Witness Lee Hill, 55, said he heard a loud noise from his office and saw "panic and shock" in the street outside.

"People were crying and a bit distressed," he said. "People were coming off the bus dazed and shocked."

Salah Arif, 32, said the bus was travelling between 20 and 25 miles per hour when it appeared to hit a roadside tree.

"The bus was swerving around (afterwards)," he said. There were pieces of metal and branches and glass everywhere."