A senior Chinese diplomat has repeated his country's opposition to the possible deployment of an advanced U.S. missile defense system in South Korea.

South Korea and the U.S. have begun formal talks on the deployment of a Terminal High Altitude Area Defense (THAAD) battery in South Korea after North Korea conducted its fourth nuclear test and test-launched a long-range rocket earlier this year.

Chinese Vice Foreign Minister Li Baodong expressed "firm opposition" to the possible deployment of a THAAD unit to South Korea during this week's regular meeting in Washington with Rose Gottemoeller, the U.S. undersecretary of state for arms control and international security, the Chinese ministry said in a statement posted on its website Friday.

China has long voiced opposition to the THAAD battery in South Korea, claiming that it could also target Chinese territory.

Both Seoul and Washington officials have dismissed such concerns, saying the U.S. missile shield is defensive in nature and focuses on North Korea's missile activities.

Gottemoeller has reportedly said that the U.S. hopes to hold talks with China to address Chinese concerns about a THAAD deployment to South Korea. (Yonhap)