The authorities in the United Arab Emirates (UAE) have arrested three political activists who called for democratic and economic reforms.
They include outspoken economics professor Nasser bin Ghaith, said a lawyer and fellow activist on Sunday.
Also detained were Fahad Salem al-Shehhi and Ahmed Mansour, who took part in an online pro-democracy forum.
Mr Mansour was arrested on Friday in Dubai after he signed a petition in favour of an elected parliament.
Emirati intellectuals and activists, inspired by popular uprisings sweeping the Arab world, petitioned the UAE president on 9 March to introduce direct elections and invest parliament with legislative powers.
The UAE is an alliance of seven sheikdoms run by ruling families. The parliament, based in the capital Abu Dhabi, serves as an advisory body.
Its 40 members are either directly appointed by the ruling sheikhs or elected by citizens hand-picked by the rulers to vote.
There are no official opposition groups and political parties are banned.
Several Gulf states have been rocked by pro-democracy protests inspired by the revolutions in Tunisia and Egypt, including Bahrain, Yemen, Oman and Saudi Arabia.