The Syrian Human Rights League and six other organizations say 79-year-old Haitham Al-Maleh was also convicted of "weakening national sentiments," a term often used against those who challenge the regime.

The groups called Sunday's sentence "harsh and unjust." Al-Maleh has been under arrest since October. He was jailed from 1980 until 1986 for demanding constitutional reforms. He is known to suffer from diabetes and thyroid problems.

Syrian President Bashar Assad released hundreds of political prisoners after taking power in 2000, but also he clamped down on liberals, showing that there were limits to dissent.