Trouble in the House of Saud

By Roger Hardy BBC Middle East analyst

For the Saudi princes, the timing of the attacks on foreigners in Riyadh is especially painful.

The relationship with the US has long been a source of tension

It is not just that they occurred on the eve of a visit by the US Secretary of State Colin Powell.

They came only a few days after the US said it would withdraw its 10,000 military personnel from the country by the end of the summer.

Their withdrawal had long been one of the main demands of the al-Qaeda leader, Osama Bin Laden - and the princes must have hoped their departure would ease the pressure on them from radical Islamists.

Pockets of 'decadence'

But even when the military personnel have gone, some 30,000 American civilians will remain - together with tens of thousands of Europeans, Canadians, Japanese and other expatriates.

Most live in walled compounds, where alcohol flows and the sexes mingle - and for militant Islamists the compounds are symbols not just of a resented Western presence, but of Western decadence.

It seems likely the attacks were - as Mr Powell has suggested - the work of al-Qaeda or a group linked to it.

Only last week, the authorities published photographs of 19 men - the majority Saudis - who they said comprised a local al-Qaeda cell.

The men are on the run, following a shoot-out in Riyadh and the capture of a huge cache of weapons and explosives.

The Saudi princes must now fear that al-Qaeda is well-rooted in the kingdom - and that the group's aim is not just to eradicate the Western presence there, but to overthrow a regime it regards as illegitimate.