British police have arrested a third suspect over the bombing of a packed London Underground train which injured 30 people last Friday.

The 25-year-old man was detained by anti-terror officers in Newport, Wales, London's Metropolitan Police said in a statement.

The man was arrested at around 7pm this evening.

"A search is taking place at an address in the Newport following the arrest," police added.

Two other men aged 18 and 21 remain in custody in connection with last Friday's bomb attack.

"This continues to be a fast-moving investigation. A significant amount of activity has taken place since the attack on Friday," said Dean Haydon, the Metropolitan Police's head of counter terrorism command.

He added: "Detectives are carrying out extensive inquiries to determine the full facts behind the attack.

"We anticipate that the searches will take some days to complete and may cause further disruption.

"However it is important that we continue with these searches and I'd like to thank all those affected for their support, patience and co-operation."

Police are continuing to search a commercial property in Hounslow and two other addresses in Surrey, south-east England.