TRIPOLI, Aug. 1 (Xinhua) -- The United Nations Support Mission in Libya (UNSMIL) on Friday demanded immediate release of Ismail Abuzreiba, a Libyan journalist sentenced to 15 years in prison by a military tribunal in the eastern city of Benghazi.

The UNSMIL said in a statement late Friday that it is dismayed by the sentencing of the journalist, calling for his immediate release.

"The mission is concerned that the detention and trial appear to violate Libya's laws as well as its international obligations," the statement said.

Abuzreiba is known for opposing the eastern-based army, which controls eastern Libya.

The eastern-based authorities of Libya have not announced the reasons for Abuzreiba's arrest yet.

Libya has been torn by a raging civil war, between the GNA based in the capital Tripoli and the Libyan National Army and its allies based in the east.