In a televised speech read on his behalf, the king promised leniency to extremists 'without blood on their hands' if they surrendered themselves within a month. 'We give all those who belong to that group, which did injustice to itself and who were not arrested in terrorist actions, a chance to return to God and revise their positions,' said the royal proclamation. 'Those who accept this and choose to hand themselves over voluntarily within a period not exceeding one month starting from the date of this speech will be secure and will be treated in accordance with God's sharia in all that pertains to the rights of others.'

The amnesty is a turnaround for Riyadh, which had hitherto adopted a hardline policy in hunting down militants. The shift in tactics came just days after the kidnapping and execution on 18 June of American contractor Paul Johnson. Al-Qaeda's new strategy of targeting vulnerable foreign workers, and the security forces' apparent inability to stem the rising tide of violence, has created an atmosphere of unease among the expatriate community and prompted Riyadh to adopt a different approach.

The new-found leniency did not apply to Johnson's murderers. Abdulaziz al-Muqrin - the alleged leader of Al-Qaeda in the kingdom - was killed along with three accomplices in a shootout later the same day.

However, Riyadh's success at killing Al-Muqrin was tempered by the news that his successor, Saleh al-Oufi, is a former policeman, which will do nothing to dispel suspicions that Al-Qaeda is closely linked to members of the security forces.