'We tell this deviant group and others that if they do not return to the right path, they will meet the same fate or worse,' he said on 19 June.

Police cars and armoured vehicles sealed off the Al-Malaz district of the capital Riyadh late on 18 June, where a gun battle had taken place resulting in the death of Al-Qaeda leader in Saudi Arabia, Abdul Aziz al-Muqrin, and three associates.

The Saudi ruler has vowed not to allow militants to threaten the country's stability. 'We will not allow a wicked group led by a deviant ideology to destabilise the kingdom's security,' King Fahd said. 'The real Muslim has nothing to do with these actions and has no sympathy for those who carry them out,' he added.

However, a statement by 'Al-Qaeda in the Arabian peninsula' pledged further actions in Saudi Arabia after Muqrin's death. 'The mujahideen are continuing the jihad that they have pledged to God, and the killing of their brothers will not weaken their resolve but only increase their determination and commitment,' it said.

A website used by militants said Johnson was kidnapped after stopping at a fake checkpoint set up by militants. The militants had been given police cars and uniforms by sympathisers within the Saudi security forces, it said.