Authorities in Saudi Arabia have detained seven women’s rights advocates who campaigned for the right to drive and an end the male guardianship system since May 15, reported Human Rights Watch on Friday. This comes ahead of Saudi Arabia implementing an order allowing women to drive for the first time from June 30.

The detentions appeared to be part of a broader crackdown led by Crown Prince Mohammed bin Salman to silence any political activism, reported The Washington Post. A Saudi government statement released on Saturday, however, said that seven people had been arrested on charges that included “suspicious contact with foreign parties” but the statement did not name those who were arrested.

“Crown Prince Mohammad bin Salman’s campaign has been a frenzy of fear for genuine Saudi reformers who dare to advocate publicly for human rights or women’s empowerment,” said Sarah Leah Whitson, Middle East director at Human Rights Watch. “The message is clear that anyone expressing skepticism about the crown prince’s rights agenda faces time in jail.” The Saudi royal court in September 2017 had reportedly called several activists, including some of those who are detained now, and warned them not to speak to the media.

Among those detained include Loujain Al Hathloul who has been campaigning for years against the driving ban on women, reported Bloomberg. She was arrested in 2014 for trying to drive across the border separating the United Arab Emirates and Saudi Arabia. Women’s rights advocates Aziza Alyousef, Madeha Alajroush, Eman Alnafjan and Aisha Al Mana, Ibrahim Almodaimigh, a lawyer who has represented Al Hathloul, and Mohammed Alrabea, a Saudi male supporter of women’s rights, also are said to be detained.