Two Metro trains collided in Washington DC during afternoon rush hour yesterday, killing nine people and injuring 70.
Mayor Adrian Fenty called the crash, which happened above ground, the deadliest in the 33-year history of the city's Metro subway system.
Fire Chief Dennis Rubin said 70 people had been treated for injuries, including at least two who were critically injured.
At least one car from one of the trains was hurled on top of the other train in the accident.
Officials said one train hit another train that had stopped, but the cause of the crash is not immediately clear.
The crash happened on the heavily travelled red line at 5pm (10pm Irish time), between Fort Totten and Takoma Park stations on the northeastern outskirts of the district near the border with the state of Maryland.
Both trains were heading south into the city.
It was the first Metro crash involving a passenger death since 1982, when three people were killed in a derailment. The Metro train system began service in 1976.
The General Manager of Washington's metro system John Catoe said: 'What happened at approximately 5.02 or 5.03 (was) one train was stopped waiting to get the order to pass because of a train stopped at the platform.
'The next train came up behind it and, for reasons that we do not know, collided into the back of that train.'
The transit authority said one of those killed was a train operator in the trailing train.
