Authorities in Saudi Arabia have stepped up a warning to women not to defy a ban on female drivers by taking part in a mass driving protest on Saturday.

The country's interior minister has toughened the Saudi government line on the women drivers' campaign, saying anyone breaking the law is likely to face unspecified punishment.

Badawi Al Rasheed, a Saudi academic and expert on women's rights doesn't think many women will flout the ban, because of worries of their safety.

"We have heard there are counter campaigns to actually drive the women away from the streets, either by harming them or by crashing their cars," she said.

However, a Saudi woman said she got behind the wheel Saturday and drove to the grocery store without being stopped or harassed by police.

Despite warnings by police and ultraconservatives in the kingdom against defying the ban, at least 60 women have successfully driven.

Saudi professor and campaigner Aziza Youssef said organizers had received 13 videos and another 50 phone messages from women showing or claiming they had driven. She said they have no way to verify the messages.

Though no specific Saudi law bans women from driving, women are not issued licences.

Powerful clerics who hold far-reaching influence over the kingdom's ruling monarchy enforce the ban. Clerics warn that "licentiousness" will spread if women drive.

Activist suggests she was followed

Women's rights advocate Madeha Al Ajroush drove in similar campaigns in 1990 and 2011, and was going to drive again on Saturday, but decided against it.

She explained why in an interview with CBC News.

"At 8:00 in the morning, I called my girlfriend to meet her at the coffee shop, so we could go to a safe place and drive. To our surprise, we found four cars that are white, small [with] tinted [windows] and we didn't feel so comfortable about meeting behind the wheel, so we went around town trying to lose them and we were not successful.

"Finally, we went to a mall in Riyadh, waited and drank coffee, and figured out what to do.

"I figured what I would do is go to the toy shop and buy a small yellow car and then go to them and say, 'Hello, today is October 26th and I want to give this to you as a gift.'"

"So I did that, and they looked at me puzzled, surprised, and they grabbed the car from me and I just walked away."

"As we speak now there is another white car that is also tinted outside my door and I don't know why they're there. I haven't committed a crime," she said.

Online petition has 16,000 signatures

In the run up to the campaign, police warned that anyone disturbing public order would be dealt with forcefully.

Ultraconservative clerics also protested earlier in the week against the online petition campaign, which was launched in late September and says it has more than 16,000 signatures.

The account's website, oct26driving.org, and official English language YouTube account were hacked on Friday, according to activists.

'There were some cars that drove by. They were surprised, but it was just a glance. It is fine ... They are not used to seeing women driving here.'- Al Sawyan

Activists posted a four minute-long video on the campaign's official Arabic account that they said depicted Al Sawyan driving in Riyadh.

She wore sunglasses and her hair was covered by the traditional black headscarf worn by Saudi women, but her face was otherwise visible.

Like other female drivers defying the ban in Saudi Arabia, Al Sawyan said she has obtained a driver's licence from abroad.

 "I am very happy and proud that there was no reaction against me," she told The Associated Press by telephone. "There were some cars that drove by. They were surprised, but it was just a glance. It is fine ... They are not used to seeing women driving here."

The activists behind the campaign have said they believe the public mood is changing, with many more people - including an increasing number of men - publicly supporting the lifting of the ban.

2011 protests

In June 2011, about 40 women got behind the wheel in several cities in a protest sparked when a woman was arrested after posting a video of herself driving. Later another woman driver was arrested and sentenced to 10 lashes, but the king overturned the sentence.
 
King Abdullah gradually has introduced reforms since then. The reforms, which include allowing women to sit on the national advisory council and permitting women to vote and run in municipal elections, may have readied the deeply conservative nation for change.

But the stringent male guardian system has been left untouched. It requires women to obtain permission from a male relative to travel, get married, enroll in higher education or undergo surgery in some cases.

With files from The Associated Press