Anti-terrorism police arrest four men

LONDON, July 18 (Reuters) Anti-terrorism detectives said they arrested four men in Manchester today after a tip-off warning of ''the existence of a potential threat''.

Three men had been held under the Terrorism Act 2000 and the fourth under immigration laws. All were detained in the Longsight area of the city.

''The arrests have been made following information received by police of alleged terrorist activity and of the existence of a potential threat,'' a Greater Manchester Police spokesman said.

No armed officers were involved in the operation, the spokesman said, adding the arrests were not linked to any recent incidents or investigations.

Police in Britain and Australia have charged three people in connection with June's failed car bomb attacks in London and in Scotland, when a jeep was driven into an airport terminal building in Glasgow and set ablaze.

That attack on June 30 came 36 hours after the discovery of two cars packed with fuel, gas tanks and nails, primed to explode in central London.

Britain has been on high alert since deadly suicide bombings by four British Islamists in London on July 7, 2005 and briefly moved to its highest threat level in the aftermath of London and Glasgow bomb plots.

Numerous arrests have been made by anti-terrorism officers in and around Manchester, which is home to a large Muslim population, in recent years although in many cases those held have not been charged with terrorist offences.

However earlier this month a man from nearby Bolton, who police described as a terrorist ''sleeper'' with a treasure trove of material obtained from secret al Qaeda Internet sites, was jailed for nine years.

REUTERS LPB KN2304