The offer was made in a televised address read by Crown Prince Abdullah. 'Those who surrender voluntarily will be treated according to God's law,' he said, using some of the strongest language yet against militants for those who chose not to surrender. 'We swear by God that nothing will prevent us from striking with our full might.'

Saudi officials said the new initiative is aimed at younger militants 'who have not yet got blood on their hands'. Under the amnesty, only those who committed acts that hurt others would be prosecuted, and no one who turns himself in would face the death penalty.

Adel al-Jubeir, the foreign affairs adviser to Crown Prince Abdullah, later said the offer should not be interpreted as an amnesty, nor should it be seen as trying to broker a deal with terrorists. He said that Saudi authorities have dealt major blows to Al-Qaeda in the kingdom, including the 18 June killing of Abdulaziz al-Muqrin, local Al-Qaeda leader.

The televised offer is seen by many as an attempt to persuade critics that the ruling family is making a renewed effort to deal with the Al-Qaeda presence. 'This will appear to some as capitulation, though others will see it as an effort by the authorities to try a change of tactic,' one western diplomatic source said. 'If they promise a crackdown then they will have to deliver that once the month ends.'

Saudi police also claimed on 23 June to have discovered an Al-Qaeda team operating an internet site which has been used by terrorists to publicise their activities.

The same day, Foreign Minister Prince Saud denounced calls by radical clerics for Saudis to travel to Iraq to join insurgents battling the US military and its Iraqi allies.