One of the London bomb suspects has appeared before an extradition hearing in prison in Rome, Italy.
SUSPECTED BOMBERS ARRESTED
1: Yasin Hassan Omar, 24, wanted over bomb attempt on a Tube near Warren Street, arrested in Birmingham
2: Muktar Said Ibrahim, 27, suspected of attempting to bomb a No 26 bus in Shoreditch, arrested in North Kensington, London
3: Ramzi Mohammed, wanted over failed attempt to bomb a Tube near Oval, arrested in North Kensington, London
4. Osman Hussain, 27 (also known as Hamdi Isaac) wanted over the Shepherd's Bush attack, arrested in Rome
Magistrates could take several weeks to decide the fate of Ethiopia-born Briton Hussain Osman, 27, also known as Hamdi Issac, as Italian inquiries continue.
The hearing comes as police in London begin to interrogate three other men, also suspected of trying to bomb three Tube trains and a bus on 21 July.
A fifth man, arrested on Friday, is also being questioned over the attacks.
Of 28 people arrested in the UK in the wake of the failed bombings, 17 have been released.
But police are urging the public to remain vigilant to the threat of further attacks.
Mr Osman is being linked to the bomb attempt at Shepherd's Bush station.
Scotland Yard said he could face fast-track extradition back to the UK under the European Arrest Warrant, legislation which only came into effect in Italy last Thursday.
The suspect's court-appointed lawyer said no decision had been made on Britain's request for extradition.
Antonietta Sonnessa said the legal process was in its "initial phase", adding there were "elements in favour and against" the extradition of her client.
The BBC's Jacky Rowland said Italian police will want to establish whether the suspect travelled to Rome to simply seek refuge, or whether he could be linked to possible bomb plots within Italy.
"They will want to glean as much information as possible on his movements and contacts in Italy before agreeing to an eventual extradition," the correspondent said.
It is believed Mr Osman was brought up in Italy, where his family sought asylum.
He had been staying with his brother, who was also arrested, Italian officials said.
Hussain Osman had been staying with his brother
Police tracked him to the Italian capital by monitoring his mobile phone calls.
It is believed he left London's Waterloo station on Tuesday, 26 July, arriving in Paris later that day. The following day he was in Milan, before arriving in Rome by Thursday.
Meanwhile, in west London on Friday police detained Muktar Said Ibrahim, 27, who is the number 26 bus bomb suspect; and Ramzi Mohammed, who is wanted over the failed attempt to bomb a Tube train near Oval station.
Several west London streets were cordoned off as dozens of police, many armed and some wearing gas masks, were deployed.
A flat in Dalgarno Gardens, on the Peabody estate in North Kensington, was raided and the two men eventually surrendered.
Deputy Assistant Commissioner Peter Clarke, of the Metropolitan Police, said "specialist tactics" were used after the men had failed to comply with police requests to surrender.
'Best day yet'
In nearby Notting Hill another man was arrested after police stormed a flat on Tavistock Crescent.
The Press Association has named the man as Wahbi Mohammed, 23, brother of Ramzi.
It is thought detectives will question him over a device found on Little Wormwood Scrubs near the Peabody estate two days after the failed attacks.
Forensic searches were continuing at both properties on Saturday.
Police have now carried out detailed searches of 14 properties in London and two in Birmingham in relation to the 21 July attacks.
A fourth man, Yasin Hassan Omar, 24, was arrested in Birmingham on Wednesday. He is being linked to a bomb attempt on a Tube near Warren Street station.
Of the 28 people arrested in relation to the inquiry, 12 are still in police custody. Most are being held at the high security Paddington Green station in London.
Scotland Yard described Friday as their "best day yet" in the hunt for the 21 July bombers.
But Mr Clarke insisted the public "must not be complacent" in assuming the threat of attacks had disappeared.
"The threat remains and is very real," he told reporters.