“Nabil Rajab has been sentenced to three months in prison,” in the Muharaq case, Mohamed al-Jishi said, adding that the defence would appeal the verdict.
The activist had been released on June 27, three weeks after he was arrested for tweeting insults against the predominantly Sunni population of the province of Muharaq, according to prosecutors.
In a statement last month, prosecutors said they received complaints that Rajab “talked on social networks about the people of Muharaq in a way that questioned their patriotism and insulted them”.
Rajab is on trial in three other cases, all of which are linked to separate protests across Bahrain.
The activist had led anti-government protests following a government crackdown on Shia-led demonstrations in March 2011.
l A Bahraini court yesterday ordered the disbanding of a Shia opposition group, the Islamic Action Association, judicial officials said.
The group was found guilty of “several violations” including following a “religious ideology that calls for violence” and “not holding the association’s convention for more than four years”, according to the sources.