London (CNN)London police are treating a Friday morning incident on a train at Parsons Green Tube station as terrorism. Get the latest updates below.

September 15, 2017 12:00pm BST

What we know right now

+ Device detonated on train: Police say an "improvised explosive device" was detonated on a train in west London

+ Blast treated as terrorism: Prime Minister to chair emergency meeting as police appeal for witnesses

+ “Fireball” in carriage: Passengers took photos of a burning bucket that may have caused the blast

+ Injuries and panic: Eyewitnesses saw people with burn injuries as commuters fled Parsons Green station

+ 18 taken to hospital: No life-threatening injuries as hospital declares emergency.