The regime forces conducted the raids on Monday.
One of the activists was covered with blood when he was being taken away, according to eyewitness reports.
Saudi activists say one of the detainees is Abdullah al-Suriah, whose name is on the Saudi Interior Ministry’s wanted list for allegedly organizing anti-regime protests in the kingdom.
There have been numerous demonstrations in Saudi Arabia’s Eastern Province since February 2011, with protestors calling for political reform.
Anti-government protests have intensified since November 2011, when security forces opened fire on protestors in Qatif, killing five people and leaving scores more injured.
Activists say there are over 40,000 political prisoners in Saudi Arabia, many of them being held without trial or charges.
In October 2012, Amnesty International called on the Saudi authorities to stop using excessive force against pro-democracy protestors.
“The Saudi authorities must end their repeated moves to stifle people’s attempts to protest against the widespread use of arbitrary detention in the country,” Philip Luther, Amnesty International’s director for the Middle East and North Africa, said on October 16.
“The right of people to peaceful protest must be respected and the security forces must refrain from detaining or using excessive force against people who exercise it,” he added.