DUBAI (Reuters) - A Bahraini appeals court on Monday more than doubled the prison term imposed on the country's most prominent opposition leader, Sheikh Ali Salman, to nine years from four, a ruling that could increase political tensions in the Gulf kingdom.
Bahrain's public prosecutor said the stiffer sentence related to "crimes of promoting change to the political system by force", according to state news agency BNA.
Sheikh Salman's al-Wefaq Islamic Society denounced the decision as "provocative" and said it undermined any chance of resolving a political crisis in the Sunni-ruled kingdom tinged with sectarianism and rivalries among regional powers.
"The appeals court ruling ... will further strain the security and political situation in Bahrain," a joint statement by four leading opposition groups said.
Salman, a Shi'ite Muslim cleric, was sentenced in June to four years in prison for inciting unrest. Defense lawyers appealed in September, saying that prosecutors had presented as evidence excerpts of his speeches that were taken out of context.
Prosecutors responded with their own appeal asking the court to reverse Salman's earlier acquittal on more serious charges of seeking to overthrow the political system by force.
"He was in the habit of such incitement and promoted (it) in his speeches on various occasions, including extremist appeals in which he justified acts of violence and sabotage, provoking regime change and calling for jihad (holy war) as a form of religious duty," BNA said, quoting the prosecution.
The court extended his prison term as a result. His lawyers said they have 30 days to appeal against the ruling.
"The case stands on what Sheikh Ali Salman has said in his speeches, and there is nothing in his speeches that contained (substance reflecting) the charge against him," defense lawyer Jalila al-Sayed told a news conference.
Salman was arrested in December in a case that angered his followers and stirred unrest in the island kingdom, which has a Shi'ite majority.
Bahrain, which hosts the U.S. Fifth Fleet, has experienced sporadic turmoil since a Shi'ite-led uprising in 2011 that demanded democratic reforms and a bigger role in government.
That revolt was put down with military assistance from neighboring Saudi Arabia, which fears that Shi'ite arch-rival Iran is spreading its influence in the Arab world.
(Reporting by Sami Aboudi and Noah Browning; Editing by William Maclean and Mark Heinrich)