Riyadh, May 19 (IANS): Saudi Arabia authorities have arrested seven women's rights advocates, weeks before the kingdom is to lift its ban on women driving, Human Rights Watch said on Saturday.

The reasons for the arrests were not clear but activists said that authorities were attempting to "silence the women", according to a BBC report.

The kingdom's state news channel reported that they had been arrested for contacts with a foreign power. Saudi Arabia has strict laws requiring women to seek permission from their fathers, brothers, husbands or even sons for various decisions and actions.

Seven activists were detained including Loujain al-Hathloul, Eman al-Nafjan and Aziza al-Yousef, who have publicly opposed the driving ban, due to be lifted on June 24.

According to Human Rights Watch, both Nafjan and Hathloul signed a petition in 2016 to abolish the male guardianship system, which prevents women from travelling abroad, marrying or obtaining a passport without the permission of a male guardian.

Hathloul has been detained twice already, once in 2014 when she attempted to drive across the border from the United Arab Emirates. She was again detained in June 2017 when she arrived at Dammam airport, in the east of Saudi Arabia, but was released several days later.

Nafjan was in the headlines in 2013 when she filmed another female activist driving through the Saudi capital, before she was stopped by police. The activist was released but refused to sign a pledge that she would not drive again.

The detainees also included a semi-retired lawyer who had stepped in to represent Saudi human rights advocates in recent years, reports said.

Human Rights Watch said the activists were rounded up on May 15. It also said that the activists had received phone calls from the royal court last September warning them "not to speak to the media".

"The calls were made the same day the authorities announced that they would lift the driving ban on women," it said in a statement.

"It appears the only 'crime' these activists committed was wanting women to drive before Mohammed bin Salman did," Human Rights Watch's Middle East director, Sarah Leah Whitson, said.

Saudi Arabia lifted the driving ban on women in September 2017 as part of Crown Prince Mohammed bin Salman's "Vision 2030" programme to diversify the economy away from oil and open up Saudi society.

His reforms will also allow women to start a business without express permission from a man.