Police in Britain said Saturday that they had arrested an 18-year-old man in connection with Friday’s explosion aboard a London subway train that injured 30 people.
Police say the man was arrested by Kent police in the port area of Dover on the English Channel.
Deputy Assistant Police Commissioner Neil Basu said it was a “significant arrest.” He said the investigation was ongoing and the terror threat level remained at “critical.”
The suspect was being held for questioning under the Terrorism Act. He has not been charged or identified.
Investigators in Britain have been working feverishly since the attack occurred at the Parsons Green station to collect evidence and information about the attack.
Hundreds of officers were examining surveillance footage and conducting other investigations as the nation elevated its terrorism alert system to the highest level, the BBC reported.
Authorities said the suspect carried a white bucket containing an explosive onto the rush-hour train. When it exploded, numerous train riders suffered burns, and others were injured as they rushed away from the area of the blast.
None of the injuries were believed to be life-threatening.
The Islamic State group claimed responsibility for the attack.