DUBAI: The United Arab Emirates has arrested eight Emirati Islamists, including a state prosecutor and a former judge, rights activists said on Tuesday, widening a crackdown on dissidents over alleged threats to state security.

Thanks to cradle-to-grave welfare systems, the UAE and other Gulf Arab monarchies have largely avoided Arab Spring movements that have ousted autocratic rulers elsewhere. But they fear the rise of Islamists in Egypt and other states in the wake of democratic revolts could embolden dissent on their own turf.

The UAE arrests over the past two weeks raised to around 60 the number of dissidents detained since last year. The UAE had said in July it was investigating a foreign-linked group planning "crimes against the security of the state".

Activists say that Ali Saeed al-Kindi, a prosecutor at state courts, and Khamis Saeed al-Zyoudi, a former judge, were among those rounded up. Most of those detained since last year are from the UAE but they include an Omani and stateless residents.

Sheikh Sultan al-Qassimi, who is a cousin of the ruler of the northern emirate of Ras al-Khaimah (RAK) and also head of the Islamist al-Islah (Reform) group, was detained and taken to the UAE capital Abu Dhabi, according to a family member.

Sheikh Sultan, along with prominent Islamist Saleh al-Dhufairi, had been kept under house arrest at the RAK ruler's palaces since April. Islah has been the focal point of the security clampdown.

"We went to visit (Sheikh Sultan) on Sunday afternoon at the ruler's palace but we were told that a group of men from Abu Dhabi came and took him away," a family member, talking on condition of anonymity, told Reuters.

"They didn't tell us where he was taken to or who were those men, but it looks like an official agency as they went inside the palace and took him. We just hope he is in good health."

Dhufairi was also detained and taken to Abu Dhabi on Sunday, a family member said.

Interior Ministry officials were not available for comment.

The UAE, a significant oil exporter and Middle East business hub, tolerates no organised political opposition. But, concerned about possible Arab Spring spillover, it has acted fast to isolate dissidents, stripping seven Islamists of their citizenship last year on national security grounds.

The UAE had said the seven men had been naturalised and were of non-Emirati origin.

Islamists' demands in the UAE include more civil rights and greater power for the Federal National Council, a quasi-parliamentary body that advises the government but has no legislative power.

Diplomats and analysts say the perceived harshness of the crackdown could lead to a backlash among ordinary Emiratis and the arrests drew strong criticism from rights groups.

A source close to the UAE government told Reuters earlier this month that those detained and are being questioned "are all alleged to have been members of an illegal organisation that has organisational, financial and political links outside the UAE".

In an August 26 commentary published in a local newspaper, UAE Minister of State for Foreign Affairs Anwar Gargash rejected criticism over the arrests, calling it an attempt to smear the UAE "with very little reference to our many achievements".

Islamists in the UAE say they share similar ideology with the Muslim Brotherhood in Egypt but have no direct links with the group, seen as a mentor for Islamist groups in the region.