US Secretary of State Hillary Clinton has praised the 'brave' Saudi women who are demanding the right to drive.

However, she tried to avoid an open breach with a close US ally by saying the Saudis themselves should determine the way forward.

The Saudi driving ban has been publicly challenged in recent weeks by women who have risked arrest to get behind the wheel.

Mrs Clinton, one of the world's best-known advocates for women's rights, has come under mounting pressure to take a stand.

'What these women are doing is brave and what they are seeking is right, but the effort belongs to them. I am moved by it and I support them,' Mrs Clinton said in her first public comments on the issue.

Her carefully phrased remarks appeared to be an attempt to balance her deep-held beliefs with the need to keep smooth relations with Riyadh in an era of huge political changes sweeping the Middle East and concern about oil supplies.

The US and Saudi Arabia have seen their traditionally close ties strained in recent months as popular protests erupted in a number of Arab countries including Bahrain, where Saudi security forces were called in to restore order.

Prior to her remarks, the State Department had said Mrs Clinton was engaged in 'quiet diplomacy' on the driving ban - drawing a fresh appeal from one Saudi women's group for a more forceful US stance.

'Secretary Clinton: quiet diplomacy is not what we need right now. What we need is for you, personally, to make a strong, simple and public statement supporting our right to drive,' the group, Saudi Women for Driving, said in a statement e-mailed to reporters.

Mrs Clinton raised the issue in a telephone call with Saudi Arabia's foreign minister on Friday. She said the US would continue to support full universal rights for women around the world.