An explosion on a London Underground train on Friday morning is being treated as a terrorist incident, British police said.

The Metropolitan Police said emergency services were called to Parsons Green station in west London at 8.20 a.m. local time (0720GMT) following reports of a fire on a commuter train.

A “number of people suffered injuries” in the blast, police said and counter-terrorist officers have declared it a terrorist incident. The London Ambulance Service said 18 people were being treated for non-life-threatening injuries and eyewitnesses told BBC News that victims suffered burns.

“It is too early to confirm the cause of the fire, which will be subject to the investigation that is now under way by the Met’s counter-terrorism command,” Neil Basu, the senior national coordinator for counter-terrorism policing, said.

Online images showed a white bucket with wires protruding from it on fire inside a supermarket bag.

Prime Minister Theresa May will attend an emergency COBRA meeting later Friday.

“My thoughts are with those injured at Parsons Green and the emergency services who, once again, are responding swiftly and bravely to a suspected terrorist incident,” she said in a statement.

London Mayor Sadiq Khan said the city “utterly condemns the hideous individuals who attempt to use terror to harm us and destroy our way of life.”

He urged Londoners to “remain calm and vigilant”.

Parson Green station and the roads around it were cordoned off and police advised people to avoid the area.

Footage from the scene also showed passengers being led off a train by police.

The ambulance service said it had sent a special hazardous area response team to the scene, amid reports of a white substance being found.

Britain has been on high alert following four terror attacks in London and Manchester this year which led to 36 deaths. (Anadolu Agency)

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