A Terminal High Altitude Area Defense (THAAD) interceptor is launched during a successful intercept test, in this undated handout photo provided by the US Department of Defense, Missile Defense Agency. [Photo/Agencies]

BEIJING - The deployment of the Terminal High Altitude Area Defense (THAAD), an advanced US missile defense system, in the Republic of Korea (ROK) will "directly" impair China's security interests, a Chinese Foreign Ministry spokesperson said on Wednesday.

"We understand the ROK's legitimate security concerns, but no country should impair others' security interests when pursuing its own," Hua Chunying said at a daily news briefing.

"We believe that the deployment of the THAAD system will directly compromise China's national security interests," said the spokesperson.

The United States and the ROK started talks on THAAD after the Democratic People's Republic of Korea (DPRK) allegedly launched an Earth-observation satellite to test ballistic missile technology earlier this month.

When questioned on media reports that Chinese companies in the border city of Dandong have stopped coal trade with the DPRK, Hua said she was not clear about the reports, noting that the UN Security Council is working on a new resolution on the DPRK.

"As a responsible country, China always strictly abides by Security Council resolutions and practises its due international obligations," Hua said.