(CNN) Rights groups have slammed a "smear campaign" against Saudi women's rights activists who were arrested last week and accused of treason by local media outlets close to the Saudi government.

Several Saudi media organizations named the detainees and accused them of plotting to "violate national unity," while one online newspaper showed pictures of the activists with the word "traitor" stamped on each of their faces.

The official Saudi Press Agency did not name the seven detainees but said they were accused of "suspicious contact with foreign entities to support their activities, recruiting some persons in charge of sensitive government positions, and providing financial support to hostile elements outside the country."

Those detained attempted to "breach (Saudi) social structure and mar the national consistency," SPA reported, quoting a state security source.

Saudi daily Al Jazirah's front page on Saturday ran with the headline: "You are damned and your treason is damned." The pictures of two prominent women's rights activists, Aziza al-Yousef and Loujain al-Hathloul, featured underneath.

A screengrab from a video released by Loujain al-Hathloul shows her driving towards the Saudi-UAE border before an earlier arrest on December 1, 2014 in Saudi Arabia.

The semi-official Okaz newspaper ran a report of the arrests with the headline: "No place for traitors among us."

The reports have sparked an outcry from rights groups and activists. "Saudi Arabian authorities and government-aligned media launched a public smear campaign last night to try to discredit six prominent detained women's rights defenders as 'traitors' following their arrest this week," Amnesty International said in a statement on Saturday. The name of the seventh activist detained has not emerged in the media.

"Saudi Arabian authorities cannot continue to publicly state they are dedicated to reform, while treating women's rights campaigners in this cruel way," said Amnesty International's Middle East Director of Campaigns Samah Hadid in a statement to CNN on Monday.

A flyer circulating on social media in Saudi Arabia shows activists with a traitor stamp over each of their faces.

Some of those arrested were leading campaigners for women's right to drive in the kingdom. Loujain al-Hathloul, one of the activists arrested, is a well-known defender of women's rights and has campaigned against the driving ban.

She was previously detained in the United Arab Emirates in March and deported to Saudi Arabia, where she was held for a few days before being released, according to a source familiar with the case.

Ahead of lifting of driving ban on women, 7 female activists have been arrested, inc #OYW Ambassador @LoujainHathloul (👇 w/ @fbhutto, Mary Robinson & @KensingtonRoyal's Meghan Markle) .



🗣 We call for her immediate release. RT #FreeLoujain @amnesty 👉https://t.co/QGBG9DgBUb pic.twitter.com/pUEDxK3arP — One Young World (@OneYoungWorld) May 21, 2018

She was photographed alongside Meghan Markle, the new wife of Britain's Prince Harry, at a summit in Canada in 2016.

Aziza al-Yousef, another detainee named by rights groups and local media, is also a well-known campaigner for women's right to drive and for an end to the kingdom's male guardianship system.

The arrests came just over a month before Saudi Arabia was set to lift a ban on women drivers.

The May 19 front page of Saudi's Al-Jazirah daily shows pictures of the arrested activists, describing them as traitors.

The ban's removal was hailed as part of sweeping reforms introduced by Crown Prince Mohammed bin Salman in his rapid rise to power. But some Saudis argue that that the reforms have been largely "cosmetic," and that the crackdown on human rights defenders are part of a wider campaign to consolidate power in the kingdom.

"(The arrests) have exposed the myth that Mohammed bin Salman is a revolutionary conducting a top-down transformation of Saudi Arabia," said Madawi al-Rasheed, a Saudi visiting professor at the London School of Economics. "There is an ongoing campaign to silence everybody in Saudi Arabia from religious scholars to intellectuals, lawyers, activists, teachers, women, men: everybody."

Saudi authorities did not respond to CNN's requests for comment.

Britain's Prime Minister Theresa May greets Saudi Arabia's Crown Prince Mohammed bin Salman outside 10 Downing Street.

The 32-year-old was elevated to Crown Prince nearly one year ago, and is seen by his detractors as a royal who has tried to expand his powers and doubled down on dissent.

Last November, the young Crown Prince shocked the kingdom by ordering the arrest of dozens of high-profile businessmen and members of the royal family in what Saudi authorities called an anti-corruption drive

'Climate of fear'

Activists say the media campaigns against human rights defenders represents an "escalation" against activists that has promoted a "climate of fear."

"We are back to square one," Sydney-based Saudi activist and author Manal al-Sharif told CNN.

"We used to live in a police state; if you speak up you go to jail. And then there would be a defamation campaign against you, saying all sort of untrue things. Character assassination. We are seeing that same pattern again now," she added.

Sharif told CNN that after Saudi authorities announced plans to allow women to drive, they called her and asked her not to speak to the media about it.

Aziza al-Yousef drives a car on a highway in Riyadh, Saudi Arabia, as part of a campaign to defy Saudi Arabia's ban on women driving.

"This is really, really shocking. I had much hope for the country," Sharif said. She said she had canceled an upcoming trip to Saudi Arabia out of fear for her safety.

The events have also prompted criticism from high-profile Saudis that have praised the Crown Prince's reform agenda in the past.

Ali Shihabi, the Saudi founder of the Washington-based Arabia Foundation, tweeted Monday: "This case has been handled by the Saudi authorities in an unfortunate manner. Such serious accusations should be accompanied by much more information to give credence to any accusations. Hopefully this will be forthcoming as soon as possible."

In the meantime, international human rights activists say they have taken it upon themselves to buoy Saudi activist causes.

"As the Saudi Crown Prince tours the world presenting himself as a 'reformer,' he is arresting the women's rights activists who refuse to accept his tokenism, leaving it to us to make their voices heard," Kenneth Roth, executive director at Human Rights Watch, wrote in a tweet.

"We're expecting more arrested because the state says the campaign is ongoing ... it's clear that they want to end the rights situation in Saudi Arabia completely," said Yahya Assiri, a London-based Saudi activist.