China reiterated its opposition to the deployment of a US advanced anti-missile system in the Republic of Korea on Tuesday, after top diplomats of the US and the ROK reaffirmed their plan to deploy it by the end of this year.

ROK Foreign Minister Yun Byung-se and new US Secretary of State Rex Tillerson vowed to continue efforts to bolster the ROK-US relationship under the Trump administration in their first phone conversation on Tuesday, the Yonhap News Agency reported.

They also reaffirmed the proposed deployment of the Terminal High Altitude Area Defense (THAAD) anti-missile system. This poses a strategic security threat to China as its radar can swoop into parts of the country.

"China is opposed to the deployment of the Terminal High Altitude Area Defense system. Our firm position does not change, and will not change in the future," Foreign Ministry spokesman Lu Kang said at a daily press conference.

As for the reported retaliation on ROK products and companies in China due to the THAAD deployment, Lu said he was unaware of any such moves.

"However, we do urge related parties to stop the deployment process, to prevent the China-ROK relationship from being further harmed," he added.