Informed sources were quoted by the Arabic-language Khaleej Online news website as saying that Salem Mousa Firouz Khamis was accused of espionage for a foreign country and was sentenced to 7 years in jail (2013-2020).
The UAE sources added that a military personnel in the UAE's Armed Forces was also detained on the same charges but no information has been released about him yet.
The human rights organizations have recently criticized the UAE for maltreating the inmates, warning that the country tortures human rights activists.
In a relevant development in May, an Abu Dhabi court handed Emirati human rights activist Ahmed Mansoor a 10-year jail sentence for using his social media accounts to publish "false information" and "spread hatred and sectarianism".
Ahmed Mansoor, 48, was also fined Dh1 million (about $272,000) for insulting the "status and prestige of the UAE and its symbols", including its leaders, Abu Dhabi-based English daily the National reported.
The court cleared Mansoor of conspiring with a "terrorist organization", the paper said, adding that the ruling can be appealed through the Federal Supreme Court following a recent change in the law.
Mansoor, who was arrested on March 20 last year, had voiced support for fellow activist Osama al-Najjar when Emirati officials did not release him after the completion of a three-year sentence for tweeting about human rights abuses in the UAE.
According to Amnesty International, prior to his arrest, Mansoor faced "repeated intimidation, harassment, physical assault, and death threats from the UAE authorities or their supporters".
In 2015, Mansoor won the Martin Ennals award for human rights defenders for his work in the UAE.
The awarding body described him as "one of the few voices within the United Arab Emirates (UAE) who provides a credible independent assessment of human rights developments in the country".