Updated

A defense lawyer in Bahrain says a court has sentenced 31 protesters to 15 years in prison each for roles in firebomb attacks against security forces during an anti-government demonstration last year.

The defendants, aged 16 to 34, all come from Sitra island, a hotbed of protests since early 2011 when Bahrain's majority Shiites began an uprising seeking a greater political voice in the Sunni-ruled Gulf kingdom. The court decision Sunday could touch off more unrest.

Defense layer Mohamed al-Tajir said the charges stemmed from clashes last year when protesters pelted riot police and their vehicles with homeland firebombs. The charges included attempted murder.

Hundreds of protesters and activists have been convicted in connection with the uprising in the strategic kingdom, which is home to the U.S. Navy's 5th Fleet.