At least 18 people were injured, many with burns, following a blast early Friday on a packed rush-hour commuter train in London that police are treating as a terrorism incident.

Armed police descended on the Parsons Green underground subway station after commuters reported an explosion and a fire. London police say an improvised explosive device was the source of the fire. The police say their investigation is being supported by input from MI-5, Britain’s domestic intelligence agency.

British Foreign Minister Boris Johnson appealed for calm and said it was important not to speculate.  London Mayor Sadiq Khan said the British capital “will never be intimidated or defeated by terrorism.”

Witnesses described a scene of panic.

Chris Wildish, a passenger on the train, said there was a “massive flash of flames” reaching to the top of the train, followed by the smell of chemicals. He said a number of schoolchildren were on the rush-hour train and they were knocked around as passengers panicked as they exited the train.   

Photos taken inside the train show a white plastic bucket inside a supermarket shopping bag. Flames and what appear to be wires can be seen.

U.S. President Donald Trump tweeted early Friday, “Another attack in London by a loser terrorist. These are sick and demented people who were in the sights of Scotland Yard. Must be proactive!”

It was the fifth suspected terrorist attack in London in six months.  British Prime Minister Theresa May is set to chair a government emergency meeting Friday.
…