London-based Amnesty said it deemed Salman "a prisoner of conscience detained solely for peacefully expressing his views.”

Amnesty International called on Bahrain on Monday to free its most prominent opposition figure, a day before an expected verdict on charges that he allegedly ‘incited violence’ against the Persian Gulf Arab state's monarchy.

Sheikh Ali Salman, a Muslim cleric and head of the al Wefaq Islamic Society, was arrested in December in a case that angered his followers and stirred unrest.

London-based Amnesty said it deemed Salman "a prisoner of conscience detained solely for peacefully expressing his views.”

"The detention and trial of Sheikh Ali Salman is a blatant violation of his right to freedom of expression and demonstrates the Bahraini authorities' continued attempt to suppress political opposition and silence critical voices," it said.