Activists urging women in Saudi Arabia to defy a ban on driving say some have taken to the road in a planned challenge against the restrictions.

A protest organizer, Benjamin Joffe-Walt, says a Saudi women drove around the capital Riyadh before dawn Friday without incident. Web message boards set up by campaigners say other women also got behind the wheel.

The campaign follows the nine-day detention last month of a Saudi woman after she posted video of her driving. The plans Friday do not call for mass protests, but encourage women in the ultraconservative kingdom to begin defying the ban on their own.

There is no written Saudi law banning women from driving, but it stems from religious edicts by clerics.