BEIJING  China’s government censors have taken fresh aim at the Internet, rolling out new measures that limit its citizens’ ability to set up personal Web sites and to view hundreds of Web sites offering films, video games and other forms of entertainment.

The authorities say the stricter controls are intended to protect children from pornography; to limit the piracy of films, music, and television shows; and to make it hard to perpetuate Internet scams. But the measures also appear devised to enhance the government’s already strict control of any political opposition.

In various pronouncements, top propaganda and security officials have stressed anew the need to police the Internet on ideological and security grounds.

The “Internet has become an important avenue through which anti-China forces infiltrate, sabotage and magnify their capabilities for destruction,” wrote the public security minister, Meng Jianzhu, in the Dec. 1 issue of Qiushi, a magazine published by the Communist Party’s Central Committee.