Seoul’s Defense Ministry expressed discomfort over Beijing’s repeated opposition to the U.S.’ possible deployment of an advanced missile defense asset to the peninsula on Tuesday, escalating tension with China over the sensitive security issue.

“A neighboring country can have its own position about the U.S. Forces Korea’s deployment of THAAD (Terminal High-Altitude Area Defense system),” Ministry spokesperson Kim Min-seok told reporters during a press briefing.

“But it should not attempt to exert influence on our defense security policies.”

Kim’s remarks came the day after visiting Chinese Assistant Foreign Minister Liu Jianchao urged Seoul to “importantly think about Beijing’s attention to and concerns over the deployment of THAAD to the peninsula.”

Liu’s remarks on THAAD were the latest in a series of statements by senior Chinese officials against the U.S.’ core missile defense asset, which Beijing believes could potentially threaten its security with its long-range radar that can gather intelligence on China’s military installations.

During the press briefing, the ministry spokesperson also stressed the THAAD issue was regarding how to counter North Korea’s escalating missile and nuclear threats, indicating that THAAD, should it be installed here, would not threaten China.

“The issue originated from the efforts to deter and counter North Korea’s increasing threats,” Kim said, underscoring that the ministry puts the security of South Korean citizens before any other issue.

“Should the U.S. make a request for consultations over the issue, our Defense Ministry will make an independent decision in consideration of the military efficacy and national security interests.”

Kim added that Seoul has no plans to purchase THAAD from the U.S. and that it would push to develop its own set of missile interception systems to build an independent low-tier missile defense program, called the Korea Air and Missile Defense system.

Observers said Kim’s expression of discomfort toward Beijing may be a response that has been coordinated among related government agencies. His remarks came amid increasing criticism of Seoul’s lukewarm stance over the issue that some argue involves “military sovereignty.”

Later in the day, Assistant Secretary of State for East Asian and Pacific Affairs Daniel Russel also expressed displeasure over Beijing’s opposition to THAAD after talks with Seoul’s Deputy Foreign Minister, Lee Kyung-soo, over a set of bilateral and regional issues.

“Well, I find it curious that a third country would presume to make strong representations about a security system that has not been put in place, and that is still a matter of theory,” he told reporters.

The THAAD issue has emerged as a tricky diplomatic issue that has pressured South Korea to choose between the U.S. and China at a time when Seoul wants to maintain a security alliance with the former and strategic partnership with the latter.

Washington has already conducted a site survey to install THAAD batteries, although it has yet to begin any official consultations with Seoul over the issue. Seoul has so far maintained strategic ambiguity, saying there has been “no request” from the U.S., “no consultations” with the ally and “no decision” reached.

By Song Sang-ho (sshluck@heraldcorp.com)