Human rights groups questioned Saudi Crown Prince Mohammed bin Salman's reform agenda on Saturday after prominent women's rights activists who campaigned for the right to drive were arrested and branded "traitors" by government-aligned media outlets.

Amnesty International and Human Rights Watch called on the authorities to release the detainees, identifying six of them as Eman al-Nafjan, Lujain al-Hathloul, Aziz al-Yousef, Aisha al-Manea, Ibrahim Modeimigh and Mohammed al-Rabea.

The activists, both women and men, have campaigned for a woman's right to drive, which the conservative kingdom is set to grant from next month after banning it for decades.

The decision hailed as proof of a new progressive trend under Mohammed bin Salman, who has presented himself as a reformist but has been accompanied by a crackdown on dissent.

THREAD: Who are the 6 human rights defenders that #SaudiArabia detained and smeared? #عملاء_ِِالسفارات? No. They are brave activists.



More on them below. pic.twitter.com/ZskOvqJfAo — Kareem Chehayeb | كريم شهيب (@chehayebk) May 19, 2018

"Saudi Arabia cannot continue to publicly proclaim support for women's rights and other reforms while targeting women human rights defenders and activists for peacefully exercising their rights to freedom of expression, association and assembly," said Samah Hadid, Amnesty's Middle East Director of Campaigns.

A government statement said seven people had been arrested for suspicious contacts with foreign entities and offering financial support to enemies overseas, without elaborating.

A state security spokesman did not identify the detainees, but online news site Sabq, seen as close to the authorities, linked them to the arrests of the women's rights activists.

Authorities said that they were still identifying others allegedly involved in activities that "encroach on religious and national constants," and fellow activists said others were arrested but the total number was not immediately clear.

'Genuine Saudi reformers'

Amnesty described it as a "chilling smear campaign" designed to intimidate and discredit the human rights activists, whose faces have appeared online and on a newspaper front page labelling them as traitors.

"Crown Prince Mohammed bin Salman’s 'reform 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."

Women will be allowed to drive starting in Saudi Arabia on 24 June. Activists and analysts say, however, that the government is keen to avoid rewarding activism, forbidden in the absolute monarchy. The authorities also may aim to avoid antagonising the sensitivities of religious conservatives opposed to modernisation.

#Saudi @al_jazirah newspaper front page features 2 absolute most amazing #Saudi feminists you could possibly know of: @LoujainHathloul & @AzizaYousef. The title, in bold red letters, smears all arrested: “You & your betrayals failed”. I have no words. Never thought I’d see this. pic.twitter.com/hnj8teZ9Ps — Nora Abdulkarim نورة الدعيجي (@Ana3rabeya) May 19, 2018

"It appears the only 'crime' these activists committed was wanting women to drive before Mohammed bin Salman did," said Whitson.

In addition to agitating for women's right to drive, Nafjan and Hathloul signed a petition in 2016 seeking an end to the kingdom's male guardianship system, which requires women to obtain a male relative's consent for important decisions. Hathloul was previously detained at least twice for her activism.

Women who previously participated in protests against the driving ban told Reuters News Agency last year that two dozen activists had received phone calls instructing them not to comment on the decree lifting it. Some of those arrested this week nonetheless continued to speak out.

Dozens of clerics seen by the government as dabbling in politics were detained separately last September, a move that appears to have paved the way for lifting the driving ban, which is part of a reform programme aimed at diversifying the economy away from oil and opening up Saudis' cloistered lifestyles.