Prominent women's rights activists including Samar Badawi appeared in a Saudi court on Thursday over charges linked to their human rights activism.
Badawi is the sister of Saudi blogger Raif Badawi who was sentenced to 10 years in prison in 2012 for criticism of officials in the kingdom.
It was the first time Samar Badawi had appeared in court since her arrest on July 30, 2018. She was apprehended along with Nassima al-Sadah, a women's rights activist from Saudi Arabia's Eastern Province, and Amal al-Harbi.
It was unclear how many detained activists would appear. The European Saudi Organisation for Human Rights said Thursday's hearing was taking place in the Specialized Criminal Court, a counterterrorism court that often tries activists and political dissidents.
Under Saudi Arabia's terrorism law, the activists face 20 years in prison.
Amnesty International's Philippe Nassif said he was concerned the activists would not have a fair trial or due process, and urged the United States to take action for their release.
"Among those detained are three American citizens," Nassif told Al Jazeera.
"It is a travesty that the US administration under President Donald Trump has not held the Saudi authorities accountable for egregious human rights abuses."
Legal representation remains unclear, though rights groups have said the activists' lawyers were not present during previous court appearances or interrogations.
"Saudi Arabia's continued detention of women's rights advocates is a stain that won't go away until these sham trials are put to an end," Adam Coogle, Middle East Researcher at Human Rights Watch told Al Jazeera.
He said that the charges Baddawi and other Saudi women's rights activists on trial may face are "likely to be frivolous and related to their peaceful human rights work".
Saudi rights group ALQST said Badawi and other women activists had been subjected to "severe and brutal torture and sexual harassment" while being held.
Human Rights Watch described the arrests as part of an "unprecedented government crackdown on the women's rights movement", which began just weeks before the lifting of a women's driving ban a year ago.
"ALQST has long expressed the concern about the profoundly unfair nature of trials in Saudi Arabia with complete lack of transparency and failure to adhere to international standards," Drewery Dyke, from ALQST, told Al Jazeera.
"We believe Samar Badawi is a prisoner of conscience and we call for her unconditional release."
Torture?
Raif Badawi's wife, Ensaf Haidar, and their three children live in Canada. Canadian Foreign Minister Chrystia Freeland condemned Samar Badawi's arrest last year and called for her release - a move that riled Saudi authorities.
The Saudi government accused Canada of trying to "meddle with Saudi sovereignty" and recalled their ambassador from Canada while expelling Ottawa's ambassador to the country.
The Saudi authorities accused the activists of "contact with foreign entities with the aim of undermining the country's stability and social fabric".
The Saudi press branded the activists "traitors" and supporters of the crackdown described them as "agents of embassies" on social media.
Rights organisations documented numerous cases of alleged torture and ill-treatment of the detained activists in recent months.
Amnesty cited victims' testimony that masked men severely tortured and sexually harassed some of the women.
