US-based Human Rights Watch (HRW) has condemned the UAE’s detention of Ahmed Mansoor, a political activist, in the wake of a petition for more democratic representation.

HRW called on the UAE authorities to disclose the whereabouts of Mansoor, who was arrested in his flat on 8 April.

“United Arab Emirates authorities should immediately disclose the whereabouts of leading rights activist Ahmed Mansoor, the reason for his detention and any charges against him,” HRW said in a statement released on its website.

The arrest comes after a group of 140 political activists called for greater democratic rights for Emiratis in a petition addressed to UAE President and Abu Dhabi ruler Sheikh Khalifa bin Zayed al-Nahyan.

Political parties are illegal in the UAE and democratic participation is limited to the election of a 40-strong advisory body, the Federal National Council, by a small group of citizens.

Mansoor had been one of the petitioners. He is also a member of UAE online political forum Hewar, which is blocked in the country. His arrest was followed on 9 April by the detention of another member of the forum, Fahad Salem al-Shehhi, and Nassar bin Ghaith, a lecturer at the Abu Dhabi branch of France’s Sorbonne University, according to Reuters.

Bin Ghaith, who has been critical of the government in the past, in a recent article criticised GCC governments for spending their way out of the political unrest that had engulfed the region and had led to regime change in Tunisia and Egypt.

“No amount of security – or rather intimidation by security forces – or wealth, handouts, or foreign support is capable of ensuring the stability of an unjust ruler,” Bin Ghaith wrote.

HRW criticised the government reaction to the petition.

“We believe the detention of Ahmed Mansoor is aimed at scaring and intimidating others in the UAE who may wish to make public their demands for democratic reforms,” said Sarah Leah Whitson, Middle East and North Africa director at HRW. “While other governments in the region are discussing democratic reforms, the UAE government is digging in its heels and sticking to outmoded repressive ploys.”