Bahrain's highest court has today upheld prison sentences against 13 leaders of the 2011 uprising.

A defence lawyer said that the ruling could stir up further unrest in the US-allied Gulf Arab state.

The case has drawn international criticism from rights groups.

US officials were keen for acquittals to help restore calm in a country it counts as a regional ally against Iran.

Bahrain has been in political turmoil since a protest movement led by majority Shia Muslims began in February 2011 during a tide of revolts against governments across the Arab world.

Bahrain accuses Shia power Iran of encouraging the unrest.

The sentences, originally handed down by a military court in June 2011 and upheld by a civilian court in September last year, range from five years in prison to life sentences.

Speaking in Manama, lawyer Mohammed al-Jishi said: "This verdict is final, there are no more appeals possible, it is the last stage of litigation."

Up to 20 uprising leaders were sentenced, but only 13 filed appeals.

The remaining seven men were tried in absentia because they were out of the country or in hiding.

Bahrain's main opposition Al Wefaq condemned the decision.

The men who received life sentences of 25 years, included rights activist Abdulhadi al-Khawaja and opposition leader Hassan Mushaimaa, who has advocated turning the kingdom of Bahrain into a republic.

Ibrahim Sharif, leader of the opposition Waad party and the only Sunni among those convicted in the case, is serving a five-year sentence.

The hearing was attended by a number of foreign diplomats, Mr Jishi said, highlighting fears that the outcome could have an impact on unrest in the island kingdom.