Via NY Times:
An explosion on a London Underground train on Friday morning injured several commuters, sowed panic, disrupted service and drew a heavy response from police officers and emergency workers.
The BBC, citing unnamed counterterrorism sources, said the explosion was being treated as a terrorist attack.
Britain has been hit by several deadly terrorism attacks this year: a vehicular and knife attack near Parliament in March, a suicide bombing at a rock concert in Manchester in May, and a van and knife attack around London Bridge in June.
Taken together, the terrorist violence has been the deadliest on British soil since July 7, 2005, when suicide bombers set off explosions on three subway cars and a double-decker bus in London, killing 52 people and injuring scores of others.
— Keith Walker (@KeithWalkerNews) September 15, 2017