Ten Saudi women's rights activists began their trials Wednesday, after being held without charge for nine months.

They took part in a variety of protests against Saudi policies including the (since revoked) ban on women driving, and the legal system of male guardianship.

The criminal court presented them with charges at the hearing, but did not make them public.

The women were detained shortly before the driving ban was lifted, on unspecified accusations of contact with foreign entities.

Family members and activists say the women are being tortured in prison.

Ten Saudi Arabian women's rights activists appeared in court for the first time on Wednesday after being held without charge for nine months.

The group includes Loujain al-Hathloul, Aziza al-Yousef, Eman al-Nafjan and Hatoon Al-Fassi who became famous by protesting against the female driving ban and male guardianship system, Reuters reported.

However, Saudi authorities have been criticized for the secrecy with which the trials are being conducted. No reporters, diplomats, or other observers have been allowed to attend the trials, and details of the charges the women are facing have not been made public.

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The activists were arrested last May, shortly before women were given permission to drive.

Authorities did not present any charges against them, but local media cited vague accusations of "suspicious contacts with foreign entities" and "financial support to enemies overseas," according to the International Federation for Human Rights.

The criminal court presented the charges raised against the women in Wednesday's hearing, but they were not made public, AFP reported. The hearing was closed to reporters and diplomats, AFP said, and only the activists' relatives were allowed to attend.

Family members and international groups say the women are facing human rights abuses in prison.

In an article for the Guardian, Al-Hathloul's brother, Walid, said the detention has left his sister traumatized: "Loujain told us she has been beaten, electrocuted and sexually harassed. She was attacked by interrogators who tried to take off her clothes, telling her she is a slut."

He said the Saudi government denies the allegations, but will not let independent parties investigate.

The detained women have been on the kingdom's radar for years.

In 2013, Nafjan and Yousef took part in a protest to pressure the government to end the driving ban for women. The year after that, al-Hathloul spent 73 days in custody after attempting to drive into Saudi Arabia from the United Arab Emirates, according to Reuters.

In 2016, Yousef created a petition to end the guardianship system, Reuters reported. The system requires women to have major decisions approved by a male relative,.

Read more: Saudi Arabia's repressive guardianship laws are trapping these women in desperate situations they have little chance of escaping

The buzz around the women's rights activists has threatened to tarnish Crown Prince Mohammed bin Salman's image as a progressive force of change in the Islamic kingdom.

Since he stepped in the spotlight in 2017, Saudi Arabia has lifted its driving ban, opened sports games up to women, and allowed music concerts.

A Saudi woman attends a sports game. (FAYEZ NURELDINE/AFP/Getty Images)

But the murder of Jamal Khashoggi, a prominent critic of the royal family, in the Saudi consulate in Istanbul, as well as the secretive trial of the activists, have prompted questions from its critics.

"How can we claim we are opening up to the world when we don’t even respect basic human rights?," Walid al-Hathloul wrote in the Guardian.