Interior Ministry spokesman Abd al-Rauf Chaudhry said on Sunday the prisoners, who arrived on Saturday, were transferred to a prison for questioning by law enforcement agancies.

On return, the prisoners are usually debriefed by intelligence agencies before being freed to join their families.

The last batch of 11 Pakistani prisoners returned from the US military base in Guantanamo Bay in July. Another five were released before them.

Interior Minister Faisal Salih Hayat has said before about 50 Pakistanis were taken to Guantanamo Bay after US-led forces forced the Taliban from power in neighbouring Afghanistan in December 2001.

According to media reports, the Americans have around 650 prisoners locked away in Guantanamo Bay.

Human rights concern

Human rights group Amnesty International has demanded that prisoners captured during the conflict in Afghanistan should be considered prisoners of war.

"If there is any dispute about their status, the US authorities must allow a competent tribunal to decide, as required by the Third Geneva Convention. AI has repeatedly called for these detainees to be treated in accordance with international human rights law and standards and international humanitarian law," a recent Amnesty statement said.

In March, AI sent a detailed memorandum to US President George Bush spelling out its concerns.