China has closed one of the country's largest file-sharing sites in what it says is a fight against copyright infringement, but could be seen as another measure aimed at controlling what content the country's Web users can find online.

The file-sharing site BTCHINA — a major source of overseas movies, television shows and games in the country — has been closed since Friday, and another site, VeryCD.com, was down Wednesday. A report in the Southern Metropolis Daily said other file sharing sites would be closed in the coming days.

The State Administration of Radio, Film and Television said BTCHINA did not have a license to distribute audio and video content. "SARFT has deleted our site's registration and shut down our site," a notice on the BTCHINA site said.

The owner of VeryCD.com, Huang Yimeng, wrote on his blog that his site was down due to a server problem, but he told The Beijing News in a report Wednesday that "we also don't have a license."

An official in SARFT's news office said they would post a news release about the file-sharing sites on its own Web site by Thursday morning.

Struggles over file-sharing sites aren't unique to China, with companies in the United States and Europe being accused of illegally sharing copyrighted material. But China is known to have the world's most extensive system of Web monitoring and censorship and has stepped up its efforts in recent years, with Facebook, Twitter and other social media sites already blocked in the country.

Another popular Web site, the Chinese translation cooperative Yeeyan, has stopped publishing in recent days.

The government says the main targets of its Web censorship are pornography, online gambling and other sites deemed harmful to society. Critics, however, say that often acts as cover for detecting and blocking sensitive political content.