Broadcasts by Russia Today were abruptly interrupted today and replaced with a test-screen message.
The station's editor in chief, Margarita Simonyan, told Russia's Interfax news agency the company's computer systems had apparently been infected with a virus.
She could not say when programming would return to the air, but said technicians were working to solve the problem.
Russia Today was launched on 10 December. The channel, which is financed by the Russian government, is aimed at improving the country's image with audiences in Europe, the United States, and parts of Asia.