Police have been granted more time to hold two men arrested under the Terrorism Act.

The two men are campaigners for human rights in a troubled province of Pakistan, an activist said.

Veteran human rights campaigner, Peter Tatchell, said the pair were lawful supporters of the independence movement in Baluchistan, a vast region bordering Afghanistan and Iran.

Mr Tatchell expressed concerns that the men - whom he named as Faiz Mohammed Baluch and Nawabzada Hyrbiyar Marri - could be extradited to Pakistan to face a possible death sentence.

Scotland Yard would not confirm the identities of the pair, taken into custody on Tuesday, but said they had not been arrested on extradition warrants.

A spokesman said warrants for further detention had been granted yesterday by City of Westminster Magistrates' Court, which allow police to hold the men until December 12.

One theory is that they could have been detained on suspicion of supporting the Baluchistan Liberation Army, which is on the Home Office's list of banned terror groups.

Mr Tatchell, said: "I urge the British government to not give in to pressure from the Pakistani dictator, President Musharraf."