The Metropolitan Police said that another person has been arrested in connection with the terrorist attack at Parsons Green station.
The 21-year-old man was arrested in the west London suburb of Hounslow just before midnight on Saturday, the Metropolitan Police force said, in a statement.
Earlier an 18-year-old teenager was arrested in the departure area of the port of Dover in connection with the attack on Saturday morning.
It was a "significant arrest" as the investigation continues, The Guardian quoted a statement of Deputy Assistant Commissioner Neil Basu, the senior national coordinator for counter-terrorism policing.
The arrest came 24 hours after a homemade bomb partially exploded at Parson Green tube station in west London, injuring 29 people.
"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," he said.
The ISIS has claimed the responsibility for the explosion at Parsons Green.
The Metropolitan Police has also said that further investigations will continue and the 18-year-old will be asked whether there were other conspirators involved in the attack.
The detectives will also look into the CCTV footage before and after the attack to track movements of those they suspect of involvement.
Any computer and phone owned by a suspect will be examined for clues, plus the remnants of the smouldering improvised explosive device left on the tube train will also provide forensic clues.
The London's Metropolitan Police said, "The Kent Police had arrested the man in the port area of Dover on Saturday morning under Section 41 of the Terrorism Act under which a police officer can arrest someone whom they reasonably suspect to be a terrorist."
Prime Minister Theresa May has announced that the security services are raising the terror threat level from "severe" to "critical" in the wake of the Parsons Green terror attack.
This was the fifth terrorist attack in the UK this year. But it was the only one in 2017 in which nobody died.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)