Campaigners say Walaa al-Shubbar, Aisha al-Mana, Hessa al-Sheikh and Madeha al-Ajroush have been released after being among at least 11 activists arrested last week
Saudi authorities have released a fourth women's rights advocate following her detention in a sweeping crackdown against activists, a month before the kingdom lifts its ban on women drivers, campaigners said Friday.
Walaa al-Shubbar, said to be in her 20s, was among at least 11 activists arrested last week, mostly identified by rights groups as veteran women campaigners for the right to drive and to end the conservative Islamic country's male guardianship system.
News of her freedom comes after campaigners including Amnesty International confirmed the release of Aisha al-Mana, Hessa al-Sheikh and Madeha al-Ajroush, elderly activists well-known for being part of a group that launched the first Saudi protest movement in 1990 for the right to drive.
There was no immediate comment from Saudi officials and campaigners said the terms of their release are not known.
"We call on Saudi authorities to release all other human rights defenders unconditionally and immediately," said Samah Hadid, Amnesty International's Middle East director of campaigns.
"This wave of repression in Saudi Arabia must end. These arrests are completely unjustified."
Without naming those detained, authorities last week accused the detainees of "suspicious contact with foreign parties", providing financial support to hostile nations and attempting to undermine the kingdom's "security and stability".
The names of the four released activists did not appear in reports of state-backed media that branded the detainees traitors and "agents of embassies".
The detainees include three generations of activists, among them 28-year-old Loujain al-Hathloul, also held in 2014 for more than 70 days for attempting to drive from neighbouring United Arab Emirates to Saudi Arabia, and Aziza al-Yousef, a retired professor at Riyadh's King Saud University.
Their fate remains unclear.
The Gulf Centre for Human Rights voiced concern that Hathloul, one of the most outspoken activists, was being held incommunicado, while other campaigners said the detainees had no access to lawyers and their whereabouts were unknown.
The crackdown has sparked a torrent of global criticism, casting a shadow on the kingdom's much-publicised liberalisation push launched by powerful Crown Prince Mohammed bin Salman, who recently undertook a global tour aimed at reshaping his kingdom's austere image.
The self-styled reformer has sought to break with long-held restrictions on women and the mixing of the genders, with the decades-old driving ban on women slated to end June 24.
"It seems Crown Prince Mohammad bin Salman -- who presents himself as a 'reformer', having pledged to increase women’s employment and overseeing the royal decree allowing women to drive -- sees no irony in taking credit for the symbolic change, while targeting the women responsible for pushing for it," Amnesty said earlier this week.