However, some others stayed at home, put off by phone calls from men who said they were from the Interior Ministry, reported organizers of the demonstration against an effective ban on women drivers.

Police put up checkpoints in some parts of Riyadh and there appeared to be more traffic patrols than usual on the streets of the capital - the latest sign of the sensitivity of the issue in the ultra-conservative Arab kingdom.

Five videos were published on the campaign's YouTube feed and Twitter on Saturday morning, dated October 26 and purporting to show women driving in Riyadh, the oasis region of al-Ahsa and the city of Jeddah.

Protests are illegal in Saudi Arabia, and public demands for political or social change have traditionally been interpreted by the authorities as an unacceptable challenge to the ruling al-Saud family's authority.

However, organizers said their call for women to drive on Saturday was not a political protest as they had not called for gatherings, rallies or processions of cars.

Instead they have asked women with foreign driving licences to get behind the wheel accompanied by a male relative and drive themselves when performing everyday tasks.

A website set up by the campaigners to petition the government appeared to have been hacked on Saturday morning, displaying a black background illuminated by glowing red lightning bolts.

On Tuesday, around 150 conservative clerics gathered outside the royal court in a rare protest against the pace of social reforms in Saudi Arabia, including women's rights. One prominent cleric, Sheikh Nasser al-Omar, was filmed describing the campaign for women to drive as "a conspiracy".

However, supporters of the campaign can point to increasingly public support for the idea of women driving in the media and among prominent Saudi figures.

RA/SHI