A Bahraini appeals court on Monday more than doubled a jail sentence against opposition leader Sheikh Ali Salman in a move his bloc warned would stoke unrest among the kingdom's Shiite majority.

The court increased the sentence imposed on charges of inciting violence to nine years from the original four, a judicial source said.

Salman's Al-Wefaq bloc condemned the verdict as "unacceptable and provocative", warning it "entrenches the exacerbating political crisis" in Bahrain.

The 50-year-old was originally convicted in July 2015, drawing condemnation from human rights groups as well as both the United States and Iran. Demonstrators have taken to the streets demanding his release.

Arrested in December 2014, he was also convicted last year of inciting hatred in the Sunni-ruled kingdom but acquitted of seeking to overthrow the monarchy and change the political system.

Al-Wefaq was Bahrain’s largest parliamentary bloc until its 18 MPs walked out in February 2011 to protest violence used against demonstrators.

The tiny but strategic Gulf state has been shaken by unrest since it crushed a month-long, Shiite-led uprising demanding reforms in 2011.

The Shiite-majority kingdom, connected to Saudi Arabia by a causeway, lies across the Gulf from Shiite Iran and is home to the US Fifth Fleet.

Despite the crackdown on the 2011 uprising, protesters still frequently clash with police in Shiite villages outside the capital Manama.

Source: AFP