About 40 women staged a rare demonstration in the Saudi capital Riyadh on Saturday, demanding the release of prisoners held without a trial as part of the kingdom's efforts to fight Al Qaeda insurgents, activists said.
Women clad in black gathered in front of the Interior Ministry in central Riyadh watched by a heavy police presence, a Reuters correspondent said.
"God, free our prisoners," read one poster held up by a woman.
"The women demand to free people imprisoned in the campaign against terrorism. Many people have been held up for a long time without trial, or have nothing to do with Al Qaeda," activist Mohammed Al Qahtani told Reuters by telephone later.
A Saudi security official, who spoke on a condition of anonymity, said about 20 women gathered to demand the release of their relatives, held on suspicion of having ties to Al Qaeda.
The women were told that only the courts have the right to decide on the issue, the official said, adding the government is helping the women financially while their relatives are in jail.
Amnesty International and other human rights activists have accused Saudi Arabia of having detained thousands of reform activists in its sweep against Al Qaeda which staged a campaign inside the kingdom from 2003-06. Riyadh denies this.
The protests took place at a time when hundreds of thousands of demonstrators have rallied in the streets protesting against poverty, unemployment and authoritarian rule in Tunisia and Egypt, sending shock waves through the Arab world.
In a rare sign of rising discontent in Saudi Araba, a group of Saudi web activists also launched an online campaign calling for political reform in the world's biggest oil exporter.
The Saudi campaign, which was launched on Facebook on January 29 and has 264 members so far, called for a constitutional monarchy, an end to corruption, an even distribution of wealth, and a serious solution for unemployment, among other demands.
"Before it is too late, I call the government, and the king, to reform the country and heed our requests... if they wish to continue ruling this country, " one group member, Safaa Jaber, posted on the group's wall on Friday.
"I call on our people to take on the responsibility of demanding their legitimate rights for complete reform of our country before the situation evolves into something undesirable," she said.
Activists in Egypt have used the social media websites to rally supporters online and coordinate protests.
Saudi Arabia does not allow public dissent. Last month, police detained dozens in the port city of Jeddah after they protested against poor infrastructure following deadly floods.
HRH King Abdullah of Saudi Arabia, who is around 87, has tried some cautious reforms since ascending the throne in 2005 but diplomats say his room for manoeuvre is hindered by opposition from powerful members of the royal family.