Islamic State claims responsibility for London blast; threat level raised to critical
LONDON - An Islamic State group claimed responsibility for the attack that rocked London on Friday - the fifth this year - and U.K. officials raised the terror threat to critical, meaning another attack is expected.
The attack sent panicked commuters running for cover during the morning rush hour and sparked a massive manhunt for the perpetrator, who remained at large.
Authorities said the incident was caused by an improvised explosive device that had been left inside a bucket in a supermarket cooler bag on a busy subway car.
Photos on social media showed a white bucket on fire inside the train.
