A prominent activist in the United Arab Emirates (UAE) has been sentenced to 10 years in prison for “defaming” the country on social media.

Ahmed Mansoor, a 48-year-old father of four, was arrested in March last year.

Rights group had condemned his detention, saying that he was held in solitary confinement without a lawyer.

He has also been fined one million dirhams ($272,000; £205,000) and will be placed under surveillance for three years after his release.

Mansoor was cleared of co-operating with a terrorist organisation, but found guilty of using social media sites to “publish false information that damages the country’s reputation” and to “spread hatred and sectarianism”, local media reported on Wednesday.

In 2011, he was one of five activists arrested after calling for political or economic reforms. All were later pardoned by authorities.

Four years later, Mansoor received the Martin Ennals Award for Human Rights Defenders for what was cited as his work in raising concerns about arbitrary detention, torture and degrading treatment in the UAE, in the face of repeated intimidation and harassment.

Despite being one of the wealthiest countries in the Middle East and promoting hi-tech sectors and innovations, the UAE remains restrictive on political activity.

The federation of seven states, which include Abu Dhabi and Dubai, has no official opposition and bans political parties.

In 2013, almost 70 Islamists were given jail sentences over an alleged plot to overthrow the government.

Last year, when the UAE and a number of other Arab states cut ties with Qatar, the Emirati attorney general warned that citizens expressing sympathy for Qatar could face heavy fines and prison sentences of up to 15 years.