BEIJING China said on Monday U.S. plans to bolster missile defences in response to provocations by North Korea would only intensify antagonism, and urged Washington to act prudently.
"The anti-missile issue has a direct bearing on global and regional balance and stability. It also concerns mutual strategic interests between countries," Chinese Foreign Ministry spokesman Hong Lei told a daily news briefing.
U.S. Defense Secretary Chuck Hagel announced plans on Friday to bolster U.S. missile defences in response to "irresponsible and reckless provocations" by North Korea, which has threatened a preemptive nuclear strike against the United States.
Hong said China believed efforts to increase security and resolve the problem of nuclear proliferation were best achieved through diplomatic means.
"Actions such as strengthening anti-missile (defences) will intensify antagonism and will not be beneficial to finding a solution for the problem," Hong said.
"China hopes the relevant country will proceed on the basis of peace and stability, adopt a responsible attitude and act prudently."
The Pentagon said the United States had informed China, North Korea's neighbour and closest ally, of its decision to add more interceptors but declined to characterize Beijing's reaction.
The remarks from China's Foreign Ministry come days before U.S. Under Secretary for Terrorism and Financial Intelligence David Cohen visits China to discuss implementation of economic sanctions against North Korea.
China has expressed unease at previous U.S. plans for missile defense systems, as well as sales of such systems to Taiwan and Japan, viewing it as part of an attempt to "encircle" and contain China despite U.S. efforts to ease Chinese fears.
China has responded by developing an anti-missile system of its own, announcing the latest successful test in January.