DUBAI: A Bahrain court on Thursday sentenced prominent Shia rights activist Nabeel Rajab to three years in prison over “unauthorised” protests against the Sunni Al-Khalifa monarchy, a lawyer said.

“The court has sentenced Nabeel Rajab to three years in jail over three cases of taking part in unauthorised protests,” lawyer Mohammed al-Jishi wrote on his Twitter page.

Jishi said that the defence team would appeal.

Rajab, who heads the Bahrain Centre for Human Rights, has been in custody since June 6 on charges of insulting members of the Sunni community via Twitter, only days after he had been released on bail on after a month behind bars over other charges including protests.

Rajab led anti-government protests following a brutal crackdown on Shia-led demonstrations against the regime in March 2011.

The activist has insisted on demonstrating inside Manama, unlike the main Shia opposition which now stages protests in villages, after last year's clampdown on protesters who occupied the capital's Pearl Square for a month.

Sporadic demonstrations in Shia villages have intensified since last year's crackdown, which ended month-long protests in the capital Manama.

The court also adjourned to August 23 the appeal hearing Thursday in the case of Rajab's alleged insults to residents of the mostly-Sunni Muharaq province, over which has been sentenced to three months in jail, the lawyer said.

The avid tweeter is also accused of insulting the security forces in postings that he admitted came from his account own on the microblogging website.

The Paris-based International Federation for Human Rights swiftly condemned the sentences against Rajab, who serves as FIDH deputy secretary general, and called for his immediate release.

“Arbitrarily imprisoning human rights defenders will not stop the people from aspiring to freedom and democratic change,” said FIDH president Souhayr Belhassen.

“We hope that the international community will firmly condemn this decision and will call for Nabeel's release,” she said.

Bahrain has come under strong criticism from international rights organisations over last year's crackdown on demonstrations that were inspired by the Arab Spring uprisings.