The agency did not give details on the prisoners, but said they were released within the framework of a presidential pardon.

It said a previous batch of 20 prisoners had been released in November.

It was not immediately clear how many political prisoners remained in jail. Estimates vary from between none and hundreds, depending on what criteria are used to define political prisoners, lawyers said.

Several hundred of the country's Kurdish minority were arrested during riots in northern cities that erupted after a soccer match brawl in March.

Rights activist

"There are people who are sentenced to jail terms on charges that might not be seen as political by the authorities but there are hundreds of prisoners yet to be released," lawyer and human rights activist Anwar al-Bunni said.

Al-Bunni said activists were trying to identify who had been released in the latest move.

One source said the prisoners were from all the colours of the political rainbow. "I am not certain, but I think that there are no political prisoners left," he said.

Al-Bunni said 160 other prisoners had been released so far this year.

Hundreds of political prisoners have been released since President Bashar al-Asad came to power. He introduced a measure of political freedom, but critics say authorities later cracked down again on political activists.