Nuland told reporters that "the subject of driving did come up" when Clinton spoke to Prince Saud, apparently on Friday, in the context of broader Middle East diplomacy, including about events in Yemen and Syria.
She did not provide details of the conversation between Clinton, a champion of women's rights around the world, and the Saudi foreign minister.
"I think she is making a judgment on how best to support universal human rights for women," Nuland replied when asked why Clinton has not taken a public stand in support of women's driving in the kingdom.
"There are times when it makes sense to do so publicly, and there are times for quiet diplomacy," she said.
"The secretary has been engaged, as have others, in quiet diplomacy ... on this subject," said the spokesperson who did not rule out that Clinton could switch to a public stand.
"I don't think it speaks to any final judgment one way or the other," she said.
Earlier this month, Saudi activists wrote an open letter to Clinton urging her to publicly press Saudi Arabia to let women drive, after a Saudi woman was arrested in May for defying the ban and posting her deed on YouTube.
A number of Saudi women drove cars on Friday in response to calls for nationwide action to break what amounts to a traditional ban, unique to the ultra-conservative kingdom, according to reports on social networks.
The call to defy the ban that spread through Facebook and Twitter is the largest en masse action since November 1990, when a group of 47 Saudi women were arrested and severely punished after demonstrating in cars.
The protests are the climax of a two-month online campaign riding the winds of the so-called Arab spring which has spread mass revolts across the region and toppled two regimes.
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