Authorities in London and Rome say they believe three fugitives from last week's failed bombing attempts in London have been captured.

After a series of dramatic police raids, authorities say they now think they hold all four of the suspects who were wanted in the attempted bombing last week of three subway trains and bus in London.

Police captured two of the men in the London neighborhood of Notting Hill.  One is identified as Muktar Said Ibrahim, 27, who came to Britain from Eritrea in 1990.  Police say the other man detained has identified himself only as Ramzi Muhammad.

Italian authorities say another suspect has been arrested in Rome. He is identified as Osman Hussain, a British national of Somali descent.

The first arrest in the case came on Wednesday, when British police captured a 24-year-old native of Somalia, Yasin Hussan Omar, in the central English city of Birmingham.

The arrests come as British police maintain their highest state of alert since World War II following attacks on July 7 by four British Muslim suicide bombers who killed 52 passengers on London's subway and bus network.

The chief of the London police anti-terrorism branch, Peter Clarke, says Friday's arrests are an important development, but more tough work lies ahead for the police and public alike.

"Despite the progress that has been made with the investigation, we must not be complacent," he said.  "The threat remains and is very real.  The public must be watchful and alert.  I would like to reassure the public that we are doing all we can to keep you safe."

A witness to one of the London arrests told reporters about a tense showdown between one of the suspects and armed police, who demanded he come out of his hiding place dressed only in his underwear.

One witness explained, "Then he said to them, 'Why do you want me to come out with just my underwear on?' 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 we know you are not a risk to the police or the public.'"

The man complied, and was then dressed in a white forensic protective suit provided by police. He was later taken away in an unmarked car to the high security Paddington Green police station, where all three of the suspects arrested in Britain are being held.

As for the man captured in Rome, British police say they will be seeking his return to London on a European arrest warrant.