BEIJING — China’s Xinhua News Agency published rules giving the government service sole power to regulate the operations of foreign news agencies, marking a further tightening of press controls in the world’s biggest communist-ruled nation.

Foreign news agencies are barred from directly soliciting subscribers in China and must use agents designated by Xinhua, under the rules released yesterday by the state-run agency and posted on the government’s official Web site.

The rules give Xinhua the right to select the information released by foreign agencies and to delete any materials that it deems inappropriate.

China has been clamping down on the press, even as the government prepares to open the nation to unprecedented global scrutiny during the 2008 Olympic Games. Officials have pledged to allowed unimpeded access to foreign journalists during the games, which the government is counting on to showcase two decades of pro-market changes that helped China’s economy grow more than tenfold to become the world’s fourth largest. Xinhua formulated the measures “in accordance with national laws, administrative regulations, and the relevant regulations of the State Council,” the agency said.

Foreign news agencies are subject to approval by Xinhua and may face warnings, demands for rectification, suspension, or cancellation of their qualifications to release information for breaching the rules, the statement said.

Under the rules, foreign agencies must not release information that undermines China’s national unity, sovereignty, or territorial integrity; endangers China’s national security, reputation and interests; or violates China’s religious policies or preaches “evil cults or superstition.”

The regulations also ban incitement of hatred or discrimination among ethnic groups, spreading false information, disrupting China’s economic and social order, or undermining China’s “social ethics” or cultural traditions.