Detained activists in Saudi Arabia, including those who campaigned for the right for women to drive, have been sexually harassed and tortured in prison, Amnesty International says.
One of the activists reportedly attempted to take her own life repeatedly inside the Dhahban Prison.
"Only a few weeks after the ruthless killing of Jamal Khashoggi, these shocking reports of torture, sexual harassment and other forms of ill-treatment, if verified, expose further outrageous human rights violations by the Saudi authorities", said Lynn Maalouf, Amnesty International's Middle East research director.
In a crackdown in May, Saudi Arabia detained at least 10 women and seven men on national security allegations related to their human rights work, Amnesty said, including Loujain al-Hathloul, Eman al-Nafjan and Aziza al-Yousef who had campaigned for the right to drive.
The ban on female drivers was lifted in June.
Citing three separate testimonies, Amnesty said the activists were repeatedly tortured by electrocution and flogging, leaving some unable to walk or stand, and one was made to hang from the ceiling.
Some of the prisoners had uncontrollable shaking of the hands and marks on their bodies, according to the testimonies.
Saudi Arabia is already under the international spotlight after the murder of journalist Jamal Khashoggi at the Saudi consulate in Turkey on October 2.
"Saudi authorities are directly responsible for the wellbeing of these women and men in detention. Not only have they been deprived them of their liberty for months now, simply for peacefully expressing their views, they are also subjecting them to horrendous physical suffering," Maalouf said.
"The Saudi authorities must immediately and unconditionally release detained human rights defenders who are being held solely for their peaceful human rights work and launch a prompt, thorough and effective investigation into the reports of torture and other ill-treatment with the view of holding those responsible to account."
Others who remain in prison include writer and activist Mohammad al-Rabea and Ibrahim al-Modeimigh, a human rights lawyer.