China's foreign ministry expressed "deep concern" on Sunday as Seoul and Washington agreed to begin talks on the deployment of an advanced American missile defense system to South Korea following the North's long-range rocket launch.

Hours after North Korea claimed it had successfully put a satellite into orbit, South Korea and the U.S. announced that they would begin talks on the deployment of the Terminal High-Altitude Area Defense (THAAD) battery to South Korea. The launch is widely viewed as a covert ballistic missile test to advance the development of delivery vehicles capable of carrying nuclear warheads.

The Chinese foreign ministry said that "China's position on the issue of anti-missile is consistent and clear" in a faxed statement to Yonhap News Agency.

"Countries, when pursuing their own security, should take into account others' security interests as well as regional peace and stability," the statement said.

If the THAAD battery is deployed to South Korea, it would further raise tension on the Korean Peninsula, the statement said, adding that, "It is hoped that relevant countries would approach the issue with caution."

North Korea's defiant launch of the long-range rocket and the Jan. 6 nuclear test proved that China's diplomacy again failed to change North Korea's provocative behavior.

China, North Korea's diplomatic and economic lifeline, has resisted calls to hand down crippling economic sanctions on North Korea following its latest nuclear test.

Analysts say China's leadership is reluctant of tougher sanctions against North Korea because a sudden collapse of the regime could spark a refugee crisis at its border and lead to a pro-U.S., democratic Korea on its doorstep.

Even before North Korea's fourth nuclear test and the rocket launch, China has publicly opposed the deployment of the THAAD battery to South Korea, arguing that it could also target China.

South Korea has refuted China's claim and blamed its neighbor for trying to "influence" Seoul's own security policy.

China's anxiety over the THAAD battery in South Korea has illustrated how difficult it is for South Korea and China to develop common security interests in Northeast Asia, despite their booming economic relations. (Yonhap)