A Somalia-born British citizen believed to be one of the four suspects in the July 21 failed London bombing was arrested in Rome.
Italy's interior minister Giuseppe Pisanu said Osman Hussain, a naturalized British citizen, was picked up by Italian police in an operation which was still ongoing.
Hussain is accused of planning to plant a bomb at Shepherd's Bush underground station in west London. He was seen on closed circuit television carrying a backpack.
"The arrest made a short while ago in Rome of the Somali Osman Hussain, a naturalized British citizen, the fourth attacker on July 21 in London, is really deserving of praise," Pisanu said in a brief statement.
The operation was "being carried out in the context of international cooperation," he added, without giving further detail.
An official at the British Embassy in Rome said the arrest was carried out as part of a joint investigation between Rome and Scotland Yard. Geoffrey Watson, an embassy spokesman, said he couldn't comment further because the investigation was still under way.
Police in London on Friday arrested three men in the city's Notting Hill neighborhood and said they were all linked to the failed July 21 attacks on three underground trains and a bus.
Police did not identify the suspects, but British broadcast media reported that at least two of the three men being sought in the failed bombings had been taken into custody, the AP reports.