Sheikh Ali Salman, a Shi’ite Muslim cleric and head of the al Wefaq Islamic Society, was arrested in December in a case that angered his followers and stirred unrest.
Bahrain, which hosts the U.S. Fifth Fleet, has experienced sporadic turmoil since mass protests in 2011 led by majority Shi’ites demanding reforms and a bigger role in government. That uprising was put down with military help from Saudi Arabia.
The prosecution accuses Salman of promoting the overthrow of the political system by force, inciting violence and supporting attacks that caused the deaths of 14 policemen. He denies the charges and has dismissed the trial as bid to muzzle dissent.
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.
In a statement, the government said the "serious charges" against Salman were rightly regarded as a criminal offence, and that he had been afforded full legal rights and due processes.
"Ali Salman’s case relates to criminal charges, specifically incitement of hatred, as well as inciting violence. The charges and subsequent trial are wholly unrelated to any political views he may hold," the statement said.
"Freedom of expression is protected by Bahrain’s constitution and the government continues to uphold it robustly."
If convicted, the 49-year-old Salman faces up to 10 years in jail, his defence team says. He also faces three other, lesser charges, including inciting hatred and insulting the Interior Ministry.
The Sunni-ruled kingdom says it has made strides in political reform and increasing oversight on security forces. Opponents and rights groups like Amnesty say abuses continue.
With a political accord remaining elusive, there has been an increase in deadly bomb attacks on Bahraini security forces.
