Police arrested an 18-year-old man Saturday in connection with the terror attack at a London Underground station Friday that injured nearly 30 people, London's Metropolitan Police said.
The teen was arrested in the port area of Dover, 80 miles southeast of London, reports said.
Police called the arrest “significant” and said the investigation continues. The teen will be brought to a south London police station for more questioning, reports said.
"This arrest will lead to more activity from our officers. For strong investigative reasons, we will not give any more details on the man we arrested at this stage," Deputy Assistant Commissioner Neil Basu, the senior national coordinator for counterterrorism policing, said in a statement.
Authorities have also alluded that there may be more than one person involved in the attack.
Officials in the U.K. said Friday that the blast on a subway at Parsons Green Station was caused by an improvised explosive device, or IED — one that is believed not to have detonated entirely. The blast injured 29 people, including a child.
A photo circulated on social media showed what is purported to have been the bomb, a charred white bucket inside a bag with wires and flames coming out of it.
Police scoured CCTV footage and questioned dozens of witnesses in order to locate those responsible.
The suspect was being held for questioning under the Terrorism Act. He has not been charged or identified.
Police said the terrorist threat level remains at "critical," meaning another attack may be imminent.
The station where the explosion took place reopened Saturday with a heavy police presence, reports said.
ISIS has claimed involvement in the blast, reports said.