Washington, June 23 (DPA) Six people were killed and about 70 injured when two subway metro trains collided here during the late afternoon rush hour Monday, authorities said.

The above-ground collision occurred about 5 p.m. (2100 GMT) just inside Washington, near the Maryland state line. One train had apparently stopped between stations before being struck from behind by a second train.

“The scene is as horrific as you can imagine,” Washington Mayor Adrian Fenty said.

TV footages showed one heavily damaged carriage pushed up on top of another. The force of the collision tore the floor out of the moving train’s front car as it vaulted onto the stopped carriage.

The driver of the moving train was among the dead, officials said. The driver’s compartment at the front of the train was obliterated.

Both trains were inbound from the suburbs into the city during the evening rush hour and apparently not filled to capacity. A similar collision of outbound trains packed with commuters at that hour could have produced a far higher casualty toll.

Washington Fire Chief Dennis Rubin said that 70 people had been treated for injuries. Of those, 50 were “walking wounded”, 14 people suffered serious injuries and six were in critical condition.

About 200 of the city’s firefighters had been mobilized to assist with the rescue, with additional firefighters being called in from at least four outlying counties in Virginia and Maryland, Rubin said.

John Catoe, chief of the multi-jurisdictional agency that runs the Metro train and bus system in Washington and adjoining suburbs in Maryland and Virginia, said he was “extremely saddened” by the fatalities.

“We will get to the bottom and find out what happened,” he said.

National Transportation Safety Board official Deborah Hersman was on the scene late Monday to lead the federal accident probe. She said that at least nine investigators would participate from the federal agency, which probes all fatal accidents involving aviation and rail.

The accident was the deadliest in the Washington Metrorail system’s 33-year history, Washington Mayor Adrian Fenty said in a press conference late Monday.

A 1982 derailment killed three people, and a 2004 collision caused only minor injuries.