A Syrian court has sentenced a leading dissident, Kamal Labwani, to 12 years in prison on charges of undermining national security.

In his ruling Thursday, the judge said the charges against Labwani, which include contacting a foreign country and encouraging attacks against Syria, were offenses punishable by a life term. But the judge decided to issue the lesser sentence.

U.S. State Department spokesman Sean McCormack issued a statement Thursday saying that the United States condemns what he called the "harsh and unjust" sentencing of Labwani. He also expressed concern about reports of inhumane treatment of the prisoner.

Also in the statement, the United States called upon the Syrian government to immediately and unconditionally release all prisoners of conscience according to the obligations under the Arab Charter for Human Rights, which Syria ratified earlier this year.

Labwani was arrested in 2005 at Damascus airport as he returned from a visit to the United States, where he met with senior American officials.

Last month, another human rights activist, Anwar al-Bunni, was sentenced to five years in prison on charges of spreading false information about the state.

Bunni was arrested last year, after signing a petition that called for changes in relations between Syria and Lebanon.

Two other dissidents who signed the petition, Michel Kilo and Mahmud Issa, face similar charges. Their trial is due to resume next week.

The United States called the verdict against Bunni a sad commentary on the state of political freedom in Syria.

Some information for this report provided by AFP.