The United Arab Emirates has ordered 94 people to be tried on charges of trying to seize power.
The Attorney General said the alleged suspects had formed a secret group that publicly called on people to observe the teachings and values of Islam, but in fact sought to overthrow the state.
He said they had links to foreigners, including the Muslim Brotherhood.
The UAE has arrested dozens of alleged dissident Islamists, who have said they are victims of false accusations.
Political parties and demonstrations are banned in the UAE.
A statement from Attorney General Salem Saeed Kubaish said the suspects had used the media and social networking sites “to turn nationals [UAE citizens] against their government”.
“They launched, established and ran an organisation seeking to oppose the basic principles of the UAE system of governance and to seize power,” it said.
It said the group raised money through property deals and religious contributions.
Last year authorities detained more than 60 civil society activists, many connected to al-Islah, an Islamist group suspected of links to the Muslim Brotherhood.
Al-Islah says it favours peaceful reform and denies links to the international Muslim Brotherhood.
The crackdown triggered complaints from human rights groups.
The authorities have been accused of deporting and harassing human rights defenders, denying legal assistance to political detainees, and intimidating and deporting lawyers seeking to assist detainees.
The UAE comprises seven sheikdoms run by ruling families.
Several of its Gulf neighbours – including Bahrain, Yemen, Oman and Saudi Arabia – were rocked by pro-democracy protests inspired by the revolutions in Tunisia and Egypt in 2011.