"Contact [with the Express AM11] was lost at 3.40 a.m. Moscow time [11.40 p.m. GMT] and has yet not been restored," the agency's information center said.
Another Express spacecraft, Express A2, is currently broadcasting Russian television Channel One, RTR, and Kultura in the region.
Satellite operator Kosmicheskaya Svyaz refused to comment.
The satellite, equipped with 30 transponders with total capacity of 2,000 W, was put into orbit April 27, 2004. It was built jointly with France's Alcatel Space and Sodern, with some equipment made in Germany and Japan.
The spacecraft was scheduled to remain in orbit at least 12 years.