Two rush-hour subway trains collided in Washington DC, killing at least four people and injuring several others, officials say. Washington transport officials said “massive injuries” had been reported.

“Metro reports that two trains collided and one train is on top of the other train,” it said in a statement.

The crash happened above ground between the Fort Totten and Takoma Park stations on the Metro system’s red line at 1700 local time (2200 BST).

Washington Mayor Adrian Fenty said: “What we do know is that there are scores of people who have been injured. There are already four confirmed fatalities.

“It is my present understanding that this would then be the deadliest accident in the history of our Metro train transit system.”

Washington fire spokesman Alan Etter told the Associated Press news agency the crash was developing into a “mass casualty event”.

He said crews were cutting apart the trains to get people out. He said there were severely injured people, but gave no indication of how many.