British police have arrested six men under anti-terrorist laws in connection with last week's attempted bombings in London.

Police arrested on Monday four men in the central English city of Birmingham and two men on Tuesday night at Grantham railway station.

A spokesman for London's Metropolitan Police declined to confirm or deny British media reports that one of those arrested was wanted as a suspect in last Thursday's attempted bombings.

The spokesman said three of the four arrested in Birmingham were being held by police in the West Midlands while one was being transferred to a London police station, without saying which one.

Another police spokesperson said earlier that three of the four arrested in Birmingham were seized at one address.

Evacuation

"A suspect package has been found and, as a precautionary measure, evacuation has been undertaken in the vicinity," the spokesperson said.

"These operations are in connection with the incidents in London on 21 July."

The spokesperson said officers fired at one man with a Taser gun, a weapon that delivers an electric shock. 

The Birmingham arrests bring the number of people that police have said are being held in connection with the 21 July attempted bombings to nine.

Police last week arrested and were questioning five other people in relation to the botched attacks. 

Two more held

On Tuesday night, two men were arrested at Grantham railway station under the Prevention of Terrorism Act as they travelled from Newcastle to Kings Cross station in London, Lincolnshire police said.

The arrests were made after information was given by two off-duty officers from London's Metropolitan Police who were travelling on the same train.

They are to be questioned at a Lincolnshire police station later on Wednesday. 

It remained unclear if the two being held had anything to do with the planned attacks. 

"We're not prepared to discuss whether they're linked to the London bombings," a Metropolitan Police spokeswoman said.

PHOTO CAPTION

A member of an Army bomb disposal unit attends the scene as a house is searched in connection with investigations into the London bombings, in the Hay Mills area of Birmingham, central England, July 27, 2005. (REUTERS)