Altaf Ali Khattak, a senior police official, said: "The court has given us a seven-day remand for these men and we will continue our investigation."

The suspects are being held under various sections of anti-terrorism legislation and are yet to be formally charged.

Interrogation

Khattak said the detainees would be interrogated by both senior police and intelligence officials. They are the first known arrests in connection with the bombing.

Pakistani officials have said they believe al-Qaeda was behind the attack, although no claim of responsibility has been made by any group.

The country has been hit by a wave of attacks in the past 12 months  - many against politicians and security forces.

Benazir Bhutto, a former prime minister, was killed in a suicide gun and bomb attack in Rawalpindi in December last year. Officials believe that a Pakistani Taliban leader co-ordinated the assassination.