Bahrain's highest court has upheld jail terms against nine medics who were convicted for their role in last year's pro- democracy uprising.

The decision could spark further unrest in the Gulf Arab state.

The case has led to inter-national criticism of the 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 US Navy's Fifth Fleet, has accused Iran of encouraging the unrest and has promised a tough response to violent protests after talks with the opposition stalled.

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.

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