Abdullah al-Shehhi was arrested on Friday by security forces, said a statement from the Gulf Discussion Forum, which groups intellectuals in the Gulf Arab states.
His family has not heard from him and does not know where he is detained, it added.
Shehhi, a former member of the UAE armed forces who was originally from the northern emirate of Ras al-Khaimah, was one of 133 signatories of a March 9 petition calling for direct elections and a parliament with legislative powers in the UAE, which has not yet seen protests that have swept other Arab states.
Three other Emirati activists were reported arrested before him.
On April 10, Human Rights Watch denounced the arrest of Ahmed Mansoor, who was also a signatory of the petition, and called on authorities to reveal his whereabouts.
HRW said Mansoor`s arrest was "aimed at scaring and intimidating others in the UAE who may wish to make public their demands for democratic reforms."
The Gulf Discussion Forum said on April 11 that economist Nasser bin Gaith had been arrested, as had another activist, Mansur al-Shehhi.
The group has called recent arrests part of "a `protests phobia` regimes in the region are suffering from."
"The repression by Bahraini authorities of movements calling for freedom and democracy is an example," said the group, adding that Oman, which has also cracked down on pro-reform protests, is another.
Bahrain`s Sunni authorities carried out a bloody crackdown on a Shiite-led pro-democracy movement in mid-March. Omanis have also held protests calling for reform, in which several people have been killed by the authorities.
A wave of anti-government protests has spread across the Arab world after demonstrators in Tunisia and Egypt succeeded in ousting those countries` long-time leaders. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011