Sheikh Ali Salman’s jail term increased to nine years from original four on charges of incitement against government.
The Supreme Court of Appeal increased Salman’s prison sentence on charges of inciting violence and calling for anti-regime demonstrations to nine years from the original four.
The al-Wefaq opposition group, headed by Salman, denounced the court ruling as “unacceptable and provocative,” saying it “entrenches the exacerbating political crisis” in Bahrain.
Al-Wefaq was Bahrain’s largest parliamentary bloc until its 18 MPs walked out in February 2011 to protest violence used against demonstrators.
On Friday, an international human rights organization called on the US administration to demand the immediate release of the 50-year-old dissident.
“If the US government is serious about helping Bahrain escape its political crisis, it should publicly call for his immediate release so he can be part of a much-needed dialogue with the government,” Brian Dooley, with the US-based Human Rights First, said.
Sheikh Salman was arrested in December 2014 on charges of attempting to overthrow the Manama regime and collaborating with foreign powers.
He denies the charges, saying he has been seeking reforms in the country through peaceful means.
In June 2015, a Bahraini court sentenced him to four years in prison on charges such as insulting the Bahraini Interior Ministry and inciting others to break the law. He was acquitted of seeking regime change.
The Office of the UN High Commissioner for Human Rights (OHCHR) has repeatedly called on the Manama regime to release the al-Wefaq leader.
Since February 14, 2011, anti-regime protesters have held numerous demonstrations on an almost daily basis in Bahrain, calling for the Al Khalifah family to relinquish power.
In March that year, troops from Saudi Arabia and the United Arab Emirates were deployed to the country to assist the Bahraini regime with its crackdown on the peaceful protests.
Scores of people have been killed and hundreds of others injured or arrested in the crackdown.