The Chinese state-run Xinhua News Agency stated in a three-sentence dispatch that the test of "ground-based, midcourse missile interception technology" was carried out "within its territory."

"The test has achieved the expected objective," the report said, noting that it was "defensive in nature and is not targeted at any country." No other details of the test were released.

Rick Fisher, a specialist on the Chinese military, said the announcement of the missile-defense test was unusual since China conducts missile tests on a weekly basis but rarely publicizes them.

"The big news here is that they are actually reporting, however brief, on a missile test," Mr. Fisher said. "This appears to be a new trend."

In recent days, Beijing has stepped up rhetoric denouncing U.S. arms sales to Taiwan, including Raytheon Co.'s sale of Patriot missile-defense systems.

China's government also has frequently criticized U.S. missile-defense development and, along with Russia, has sought to restrict missile defenses in United Nations forums.

Chinese Foreign Minister Yang Jiechi told a U.N. disarmament conference in August that "countries should neither develop missile-defense systems that undermine global strategic stability nor deploy weapons in outer space."

Mr. Fisher, with the International Assessment and Strategy Center, said a recent published report by a senior Chinese military officer outlining China's aerospace doctrine made clear that "the air force will be developing a missile-defense mission." The missile-defense program is part of a military unit called Second Artillery Corps.

Mr. Fisher, who has written reports on Chinese missile defenses, said he thinks China will deploy a substantial nationwide missile-defense system by the mid-2020s.

"This will constitute the ultimate irony and face slap given China's very loud and vocal opposition to U.S. missile defenses in late 1990s and early this decade," Mr. Fisher said.

Asked about China's test and its past opposition to U.S. missile defenses, Chinese Embassy spokeswoman Xi Yanchun repeated that "so far, I know that the test is defensive in nature and is not targeted at any country."

Mark Stokes, a former Air Force officer and specialist on the Chinese military, said China has been investing resources for missile-defense technologies and ground-based space surveillance since the late 1980s.

"It's unclear how sophisticated the test was or what was used as a target," said Mr. Stokes, with Project 2049 Institute, a research group.

However, he noted that "there's likely a linkage between China's anti-satellite and missile-defense interceptor programs" because both use similar technology.

Mr. Stokes said China's complaints about U.S. missile-defense sales to Taiwan are dubious considering Beijing's large-scale conventional ballistic missile buildup against Taiwan. More than 1,000 missiles are now deployed near Taiwan.

"If authorities in Beijing find the sale of U.S. missile defenses to Taiwan to be against China's interests, maybe political authorities in Beijing should reduce the missile threat," he said.

In January 2007, China fired a ground-based missile into space and successfully destroyed a weather satellite. This anti-satellite system, which remains couched in secrecy, could be adapted by China for a nationwide anti-ballistic-missile system, Mr. Fisher said.

The Pentagon's latest annual report to Congress on China's military, released last spring, made no mention of Beijing's development of missile defenses, despite providing details on an array of new Chinese weapons, including missiles, submarines, aircraft and cyberwarfare capabilities.

The announcement of the missile-defense test also coincided with a Xinhua report warning that U.S. arms sales to Taiwan are harming U.S.-Chinese relations.

The Pentagon announced a $970 million contract to sell Patriot PAC-3 missiles to Taiwan in a Jan. 6 statement. The Xinhua report noted that the contract with Lockheed Martin Corp. was part of an arms package first approved by President Bush's administration in October 2008.

"Profound lessons should be drawn from history," the report said. "All previous U.S. arms sales to Taiwan have caused great damage to the Sino-U.S. relations and blocked their stable and smooth development."

China cut off military relations with the Pentagon after the October 2008 arms package to Taiwan was announced, although Beijing has been gradually resuming military ties.