China: U.S. risks antagonizing North Korea

The U.S. announcement came after North Korea recently threatened a pre-emptive nuclear attack on South Korea and the United States in response to stepped-up U.N. Security Council sanctions over its latest nuclear test last month.

Under threat, South Koreans mull nuclear weapons

The threat from the regime of young leader Kim Jong Un was part of a recent barrage of vitriolic statements, which included a vow to nullify the armistice agreement that stopped the Korean War in 1953.

Military and White House officials have said current U.S. missile defenses are adequate for the present level of threat, and President Barack Obama said in an interview with ABC News last week that he didn't think North Korea could carry out a missile attack on the United States.

"They probably can't, but we don't like the margin of error," Obama said.

The 14 additional interceptors, to be installed by 2017, would bring the total to 44, according to the Pentagon.

"The reason that we are doing what we are doing and the reason we are advancing our program here for homeland security is to not take any chances, is to stay ahead of the threat and to assure any contingency," Hagel said.

But Hong said Monday that China believes that the anti-missile issue "matters to global strategic balance and regional stability. It also matters to strategic trust between relevant countries."

North Korea on Saturday responded to the U.S. announcement by criticizing what it described as the Americans' "hostile policy" and saying it won't negotiate with them over its nuclear program.

Its nuclear weapons "serve as an all-powerful treasured sword for protecting the sovereignty and security of the country," a Foreign Ministry spokesman said, according to the North's state-run Korean Central News Agency. "Therefore, they cannot be disputed ... as long as the U.S. nuclear threat and hostile policy persist."

Tensions on the Korean Peninsula escalated in December, when North Korea successfully launched a long-range rocket, putting a satellite in space for the first time.

The United States and other Western nations called the launch a test of ballistic missile technology, and the U.N. Security Council tightened sanctions on the regime in Pyongyang.

North Korea responded angrily to the U.N. measures, vowing to carry out its third nuclear test. It made good on its promise last month, prompting the U.N. Security Council to expand sanctions further, which in turn set off the latest flurry of fiery North Korean rhetoric.