WASHINGTON - The death toll from a collision between two subway trains in the US capital Monday has risen to nine, broadcaster CNN reported Tuesday.

At least 76 people were injured in the accident that has been described as the deadliest in the Washington Metrorail system’s 33-year history.

A train that had apparently stopped between stations was struck from behind by a second train at about 5 p.m. (2100 GMT), just inside Washington, near the Maryland state line.

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

Few details about the dead have been released. The Washington Post said that the driver of one of the trains, Jeanice McMillan, 42, was among the dead. Her cabin was obliterated when her train struck a stationary one.

The accident occurred on the subway system’s red line, which serves the Maryland suburbs of Bethesda, Rockville and Gaithersburg. Commutes Tuesday were expected to be significantly delayed as work continued on clearing the tracks, reported CNN.

Local news footage 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.

Fenty told CNN that one car was “about 75 percent compressed”. Recovery workers had been unable to ascertain whether there were any bodies inside.

“We just haven’t been able to cut through it to see if there’s bodies in there,” he said.

Passengers interviewed said they had never seen so much blood. Other survivors spoke of helping fellow passengers with injured legs, arms and backs. 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.

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 to lead the accident probe. She said at least nine investigators would participate from the federal agency, which probes all fatal accidents involving aviation and rail.

It was unclear if the trains were carrying recorders, which could provide details about operations, including their speed.

The accident was the deadliest in the Washington Metrorail system’s 33-year history, Fenty told a press conference.

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