Rights groups have accused the UAE of widespread violations including jailhouse abuses against the 94 suspects on trial. The suspects included teachers, lawyers and even the cousin of one of the UAE's rulers.
Authorities have rejected the claims and have moved ahead with further arrests sweeps targeting suspected groups linked to Islamist networks such as Egypt's Muslim Brotherhood.
The UAE — which allows no political parties — has not faced any street protests or direct pressures since the Arab Spring uprisings began in the region more than two years ago.
But Western-backed officials have turned their attention to suspected Islamist cells and online activists who have called for a greater public voice in the tightly controlled country.
Prominent rights activist Ahmed Mansoor — who was jailed in some of the first UAE crackdowns after the Arab Spring — said prison terms of 15 years were given to eight suspects tried in absentia.
Ten-year sentences were handed to 60 others, including Sheikh Sultan bin Kayed al-Qasimi, who was head of a group known as al-Islah, or Reform. He is a cousin of the ruler in Ras al-Khaimah, the northernmost of the UAE's seven emirates.
At least 26 of the suspects were acquitted, Mansoor said.
Security was tight around the court Tuesday with many foreign journalists, family members and observers blocked from the session. The Abu Dhabi-based newspaper The National reported that chants of "Allahu Akbar," or God is Great, came from defendants and some relatives as the verdicts were read.
Mansoor said at least two brothers of the suspects were detained hours before the verdicts were handed down, reflecting wider trends across the Gulf as leaders attempt to quash any challenges to their rule.
Dozens of people have been jailed across the Gulf for blog posts and Twitter messages deemed offensive to rulers. Authorities across the Gulf also have claimed to have dismantled alleged espionage rings — some accused of links to rival Iran or its proxy Hezbollah.
But the UAE has been the most aggressive in moving against suspected threats from Islamist groups.
Last month, UAE officials said they plan another high-profile trial against 30 Egyptian and UAE suspects for alleged coup plots linked to Egypt's Muslim Brotherhood.
The case raised tensions with the Brotherhood-led government of Egyptian President Mohammed Morsi who is now under extreme pressure at home from protesters and military officials calling for him to step down.
In the Emirates' case against the 94 suspects, prosecutors claimed that the group al-Islah — which was headed by the ruler's cousin al-Qasimi — was influenced by Muslim Brotherhood ideology to oppose the Western-oriented system in the UAE.
The suspects rejected the claims, saying the group only supported Islamic viewpoints and conducted needed social outreach in poorer areas of the country beyond the skylines of Dubai and Abu Dhabi.
Al-Islah has operated openly for decades in the UAE under the tactic agreement that members would not get involved in political affairs.
In London, the director of the Emirates Center for Human Rights said the aim of the trial was to "silence political activists and intimidate others who may support democratic reforms."
"Allegations of torture remain without investigation and numerous fair trial standards have been violated," said Rori Donaghy.
"UAE authorities must quash these verdicts, release these individuals against whom they have presented no credible evidence and investigate the allegations of torture that have been made," Donaghy added.
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