Bahrain's highest court on Monday upheld jail terms issued against nine medics convicted for their role in last year's pro-democracy uprising, state news agency BNA reported, a decision that could further fuel unrest in the Gulf Arab state.

The controversial case has drawn international criticism of the U.S.-allied Gulf Arab kingdom, which has been in turmoil since the protests led by its Shi'ite Muslim majority were crushed by the Sunni rulers.

Bahrain, home base for the U.S. Navy's Fifth Fleet, accuses regional Shi'ite power Iran of encouraging the unrest and has promised a tough response to violent protests as talks with the opposition have stalled.

BNA quoted Attorney General Abdul-Rahman al-Sayed as saying that Bahrain's Court of Cassation rejected all appeals presented by the defendants and confirmed the previous rulings of prison terms ranging between one month to five years.

In June, the appeals court sentenced Ali al-Ekry, former senior surgeon at the Salmaniya hospital in Manama, to five years in jail and gave eight others prison sentences ranging from one month to three years. It also acquitted nine others.

Two medics previously sentenced to 15 years each did not appeal and they are believed to be in hiding or to have left the country.

The doctors were released last year after an outcry over allegations of torture during detention.

Ekry, a senior orthopaedic surgeon at Salmaniya who was convicted, among other charges, of inciting hatred and calling for the overthrow of Bahrain's rulers, said Monday's ruling might be politically motivated.

"We did not get a fair trial...We think we are a card being used by the regime to negotiate with the opposition," he told Reuters by telephone from Manama.

Mohammed al-Maskati, head of the Bahrain Youth Society for Human Rights, said Monday's verdict was final with no recourse for further appeal but there might be still a chance for a pardon by the king.

INTERNATIONAL CRITICISM

The medics' case highlights the schism in Bahraini society over the protest movement and political reform.

The doctors and nurses, who are all Shi'ites, say they were victimised for treating protesters and helping bring world attention to deaths caused by security forces.

Washington and rights groups have criticised the June ruling, with Amnesty International saying it was a "dark day for justice".

The verdicts follow an earlier trial at a military court in September, 2011 which sentenced 20 medics to prison terms of between five and 15 years on charges including theft of medical equipment, occupying a hospital and incitement to topple the state.

The Sunni Al Khalifa family used martial law and help of Saudi-led Gulf troops, to put down last year's uprising. Thousands were arrested and military trials were instituted during the martial law period.

Washington has called on its ally to talk to the opposition, but unrest continued. Protesters and police clash almost daily.

The Shi'ite opposition wants a constitutional monarchy and a more equitable political system that would allow them to have greater representation, ending decades-old discrimination against them in jobs including the army and security forces.

The Al Khalifas fear the Shi'ites want to topple them.