LONDON, England (CNN) -- All four men suspected of planting failed bombs on London's transit system on July 21 are in custody, according to sources in London and Rome.
Two bombing suspects were picked up during a raid at a government-subsidized apartment building in West London, sources close to the investigation told CNN.
The third suspect was arrested in Rome, Italy's Interior Ministry said in a statement on its Web site.
The fourth suspected bomber had been arrested Wednesday in Birmingham, central England.
Muktar Said Ibrahim, who was born in Eritrea and became a British citizen in 2004, was one of the two men arrested in London Friday. British police said Ibrahim was suspected of planting a backpack bomb on a double-decker bus in Hackney, east London.
The Italian Ministry identified the suspect seized in Rome as Osman Hussain, a naturalized British citizen of Somali origin.
Yasin Hassan Omar, 24 -- also a Somali with British residency -- was arrested Wednesday in Birmingham. Police said he was suspected of placing a backpack bomb at London's Warren Street Underground station.
Two weeks before the failed attacks, bombs on three subway trains and a bus killed 56 people, including four suicide bombers.
Dramatic video obtained by ITN of Friday's raids in London showed both men arrested -- Ibrahim and the suspected Oval Station bomber who has not been identified -- with their shirts off and hands in the air on a balcony at the Dalgarno Gardens apartments in London's North Kensington neighborhood.
Before the men came out, the video showed police with gas masks two stories below entering another flat. One of the officers was temporarily distracted by two unafraid children.
One woman, who would not reveal her name, said she heard the entire three-hour exchange between the suspects and police, who had called for "Mohammed" to come out of the building. (Eyewitness accounts)
"Police started to say to him you need to come out of the flat ... with your underwear on and your arms up in the air," she told reporters. "He was then saying to them, 'How do I know that you're not going to ... shoot me?'
"They said you need to come out into the street with your underwear on so that we know that you haven't got any explosives on you, and so that we know that you're not a risk to the police or the public."
She said she heard the exchange from her apartment window, and the man sounded like he may have been crying. After he stopped talking to the police, she said, "a more aggressive police officer got on the loudspeaker and started saying to him, 'You need to maintain contact.'"
"He didn't maintain contact. And after a while you started to see the SWAT teams arriving ... and once they came out, and after about 15 minutes of not having contact with him, you heard like the gunshots go off."
Another raid took place in Notting Hill where another man was arrested. British Transport Police said two women were also arrested under the Terrorism Act at Liverpool Street station just before 2 p.m. (1300 GMT).
A few minutes later, the station -- a major train and subway hub in the city's financial district -- was evacuated following the discovery of an unattended suitcase on the main station concourse. The station reopened shortly after 3 p.m.
The location of Friday's operation in west London is about one mile from Little Wormwood Scrubs Park, where police found a fifth undetonated bomb three days after the attempted July 21 bombings.
Police said the bomb was in a plastic container identical to the four partially-detonated devices left on three tube train cars and double-decker bus.
The neighborhood is also a little over a mile from the Shepherd's Bush Underground station, where one of the July 21 bombers failed to detonate a his bomb, then fled, running on a course in the direction of this park.
On Thursday, police arrested nine men in the Tooting area of south London.
Six were detained at one address and three at another, according to Metropolitan Police.
The Rome arrest came in a joint operation between Scotland Yard and the Italian police, a senior intelligence source told CNN.
Scotland Yard tipped off the Italian authorities and were able to trace Hussain's cell phone from London to Rome, the source said.
CNN's Jennifer Eccleston, in Rome, said it was not clear when he left London for Italy but was thought to have taken a train and stopped off in the town of Brescia, northern Italy, before heading to Rome.
He was arrested in an apartment also owned by a man also believed to be a Somali, thought to be a relative of Hussain, though a legal resident in Italy, Eccleston said.
The man owns a call center in Rome where many immigrants go to call back home, she said.
The senior intelligence source also told CNN that the man was believed to be in custody with Hussain.
They were captured by Italy's special police unit. Hussain and the other suspect were now being held at the city's main police station, she said and Hussain was currently undergoing interrogation.
London police said they would ask Italy to extradite the terror suspect arrested in Rome.