Police in Rome have arrested a man suspected of being one of the four would-be suicide bombers in the failed London attacks on 21 July.
Italian Interior Minister, Giuseppe Pisanu, confirmed the arrest of Somali-born British citizen, Osman Hussain.
Earlier, police in London arrested three men and two women as part of their investigation into the failed attacks on the London transport system.
One of the men is believed to be Muktar Said-Ibrahim, 27, who allegedly tried to blow himself up on a bus in Hackney, east London.
The other is believed to have been responsible for an attempted bombing near Oval Tube station on the same day.
The arrests were made by the anti-terrorist unit during a number of operations in different parts of the city.
Police are still questioning another suspect arrested on Wednesday in Birmingham. Yasin Hassan Omar is suspected of attempting to blow up a Tube train at Warren Street station.
Today's arrests mean all four of the prime suspects in the 21 July attempted bombings are now in custody.
Blair critical of stun gun use
Earlier, the Metropolitan Police Commissioner, Sir Ian Blair, openly criticised the use of an electric stun gun by police in Birmingham to detain a suspected suicide bomber.
Sir Ian said the firing of the Taser gun by West Midlands police during their arrest of Yassin Hassan Omar on Wednesday was an incredible risk because it could have detonated explosives.
And a British man wanted for questioning over the 7 July bombings in London was reported to have been detained in Zambia.
Haroon Rashid Aswat, from West Yorkshire, is alleged to have made contact with two suicide bombers before they carried out the attacks that killed over 50 people.
Zambian officials have confirmed that he was detained in the border town of Livingstone after entering the country from Zimbabwe.
In London the Foreign Office said it was seeking access to a British national in custody, but did not name him.
Reports from the United States suggest the Zambian authorities arrested Mr Aswat because he had allegedly been helping to plan a terrorist training camp in the US.
