Philadelphia train crash: 'Search for survivors goes on'

Officials are working to determine the cause of a train derailment which killed at least seven people and injured more than 200 others.

Seven carriages including the engine of the Amtrak train bound for New York went off the track on Tuesday evening.

Over 200 people have been treated in area hospitals, says Mayor of Philadelphia Michael Nutter. Investigators are searching the wreckage in order to confirm that all on board have been accounted for.

The BBC's Michelle Fleury reports from the scene of the crash.