The United States is damaging stability in the Asia-Pacific region by positioning a missile defense radar in Japan, according to an official in Beijing.

"Neighboring countries pushing forward the deployment of anti-missile systems in the Asia-Pacific and seeking unilateral security is not beneficial to strategic stability and mutual trust in the region," Chinese Foreign Ministry spokeswoman Hua Chunying told a regular briefing.

"It is not beneficial to peace and stability in Northeast Asia," she said.

Countries should not use "excuses to harm the security interests of other countries," Hua added, describing the situation as "deeply concerning."

The Defense Ministry has said an X-Band radar system was delivered on Tuesday to the U.S. military's communication facility in Kyoto. It is scheduled to be fully operational by the end of the year.

North Korea has carried out a series of missile tests this year, including two medium-range missiles capable of hitting Japan. Pyongyang has also threatened another nuclear test.

U.S. Defense Secretary Chuck Hagel has said two Navy destroyers equipped with missile defense systems would be deployed to Japan by 2017 in response to provocations from North Korea.

China has ratcheted up military spending in recent years, putting in place new submarines, surface ships and anti-ship ballistic missiles, which the U.S. sees as a counter to its military presence in the region.