An explosion on an underground train at a station in south-west London on Friday left several commuters injured and caused panic in the area.
Several people are said to have suffered facial burns after a reported blast in a bucket towards the rear of the District Line train. Some commuters reportedly were trampled and suffered crush injuries in the rush to escape. Islamic State of Iraq and Syria (ISIS) later claimed responsibility for the attack.
UK Police Arrest Three in Wales Over London Train Bomb Attack
British police arrested three men in south Wales over last week's bombing of a busy commuter train in west London, meaning five people are now being questioned by detectives over the attack which injured 30 people.
A 25-year-old man was arrested on Tuesday evening in Newport, while two others, aged 48 and 30, were detained at another address in the Welsh town in the early hours of Wednesday, London police said.
"This continues to be a fast-moving investigation. A significant amount of activity has taken place since the attack on Friday," said Commander Dean Haydon, head of London police's Counter Terrorism Command.
"We now have five men in custody and searches are continuing at four addresses. Detectives are carrying out extensive inquiries to determine the full facts behind the attack."
Second Man Arrested Over London Train Attack - Police
A second man has been arrested by police investigating Friday's bomb attack on a London underground train, police said.
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.
He was detained under Britain's Terrorism Act and taken to a south London police station, the force added on Sunday.
Police Nabs 18-Year-Old For Train Attack
British police hunting those behind a bomb which injured 29 people on a London train on Friday said they had arrested an 18-year-old man in a move described as significant.
We have made a significant arrest in our investigation this morning. Although we are pleased with the progress made, this investigation continues and the threat level remains at critical.Neil Basu, Senior National Co-ordinator for Counter Terrorism Policing
The man was arrested under the Terrorism Act in the southern port area of Dover.
ISIS Claims Attack
The Islamic State of Iraq and Syria claimed responsibility for the attack.
"The bombing on a metro in London was carried out by a detachment of the Islamic State" group, it said in a statement published by its Amaq propaganda agency.