British police announced on Tuesday that they arrested 13 men under the Terrorism Act in anti-terror raids in London and three English counties.

A Metropolitan Police spokesman said the arrests were made in north-west London, Hertfordshire, Luton in Bedfordshire, Blackburnand Lancashire.

Officers from the Met's Anti-Terrorist branch were backed by local forces in the "intelligence-led, pre-planned" operation on Tuesday, said the spokesman.

The suspects, aged in their 20s and 30s, would be brought to a central London police station for questioning, said the police spokesman. He added that the suspects were expected to stay at the police station for some time.

The British government said on Sunday that it is monitoring the "real and serious" threat from terrorism, but didn't warn of any specific risk.

(Xinhua News Agency August 4, 2004)