British police have arrested four men in connection with the bungled attempt to bomb London's transport network last week.
The arrests came in pre-dawn raid in the central English city of Birmingham.
In one incident, police fired an electronic stun gun to subdue a suspect. A suspicious package was found at the man's address, and more than 100 neighboring homes were evacuated as an army bomb disposal unit was called in.
A statement from the West Midlands County police says the arrests were all in connection with last Thursday's attempted bombings of three subway trains and a bus in London.
One of the men arrested was transported to a central London police station. Local news reports say he is one of the four men who planted the bombs that failed to explode. Police would neither confirm nor deny those reports.
In another development, police say two men have been arrested on suspicion of terrorism while traveling by train from Newcastle to London's King's Cross station, a major hub of the city's rail and subway network.
As the manhunt unfolded, British Prime Minister Tony Blair conferred with his Turkish counterpart, Recep Tayyip Erdogan, whose country has also been targeted by Islamic terrorists.
Mr. Blair stressed the need for international cooperation in the fight against terrorists.
"We are both, I am afraid, too familiar with terrorism and its nature," he said. " And we both agreed about how important it is that we work together to overcome this mutual threat."
Britain has been on high alert for more terrorist attacks since July 7, when a team of four British Muslim suicide bombers blew up three subway trains and a bus, killing 52 passengers.
London Police Chief Ian Blair says the search for the fugitives from last Thursday's attempted bombings must be unrelenting. As he puts it: "They are capable of killing again, and we must find them."