LONDON – At least 22 people were injured in a bomb blast on a packed London Underground train in west London on Friday.

Firefighters and paramedics were called, and witnesses told of an “extremely heavy police presence” and “quite a few people injured” at Parsons Green.

The police said it was aware of the incident and the officers are on the site.

Media technology consultant Richard Aylmer-Hall, 53, was sitting on the District Line train bound for central London when panic unfolded at about 8.20am. Several people were injured after passengers tried to escape, he said.

He added: “Suddenly there was panic, lots of people shouting, screaming, lots of screaming.

“There was a woman on the platform who said she had seen a bag, a flash and a bang, so obviously something had gone off.

“Some people got pushed over and trampled on, I saw two women being treated by ambulance crews.”