A Bulgarian court has postponed for the first time the trial against thirteen religious leaders accused of preaching radical Islam.

As the trial was getting ready to begin, the defendants' lawyer told the judges from Pazardzhik District Court that one of his clients was ill.

The new hearing has been scheduled for December 19, when experts are expected to take the stand.

The defendants face up to five years in prison in a criminal trial, which is viewed abroad as a test for the limits of religious freedom and tolerance in the country.

Prosecutors say the Saudi-financed activities of the imams have been spreading religious extremism and that they have used a local soccer team to indoctrinate boys.

Prosecutors allege that three of the imams were undermining the state by encouraging people to boycott parliamentary elections and spreading religious hatred.

The other 10 are implicated in working with Al Waqfal Islami, a Saudi-financed charity that built mosques, sent boys on trips to the Middle East and financed religious education in Bulgaria that prosecutors say embraced the Salafist brand of fundamentalist Islam.

The Bulgarian government closed Al Waqfal Islami in 2003, but prosecutors say the 13 accused continued its work without a license.