Abu Dhabi, United Arab Emirates (CNN) -- Three activists have been detained in the United Arab Emirates in the past three days, according to a fellow Emirati activist.

Blogger Ahmed Mansoor, who has called for reform in the UAE, was taken from his Dubai apartment on Friday, his wife said. Nadia Mansoor said about 10 men, including two wearing police uniforms, picked Mansoor up, took his passport and laptop and left without telling his wife where they were taking him or why.

Farhad Salem al-Shehhi, a friend of Mansoor's who helped him with his website, was detained Saturday evening, said activist Mohammed al-Mansoori. Al-Shehhi was taken from the Emirate of Ajman, where he was living temporarily while his wife studies there, al-Mansoori said. Al-Shehhi has been without a passport for seven years, he said.

The third, Nasser bin Ghaith, an Emirati writer who also maintains a website, was detained Sunday, al-Mansoori said.

Officials in the UAE have not responded to persistent queries regarding the detention of Mansoor. CNN has recently queried officials about the other detentions.

Mansoor was part of a group of 133 nationals who petitioned the president on March 9 for direct elections. The group included academics, former government officials, journalists and activists.

The petition was addressed to President Sheikh Khalifa bin Zayed Al Nahyan and the members of the Supreme Council of the seven Emirates that form the UAE.

In addition to elections, the group asked that the Federal National Council be granted legislative powers. The body only works in an advisory capacity and has no regulatory powers.