BEIJING (AP) — China remains opposed to unilateral sanctions against North Korea taken without the approval of the U.N. Security Council, the country's chief negotiator on the North's nuclear program was quoted Saturday as saying.

Wu Dawei also told his South Korean counterpart in talks Friday that China is "adamantly opposed" to the South's deployment of an advanced U.S. missile defense system that China says poses a threat to its own security, China's foreign ministry said in a statement.

Wu also pressed for a resumption of six-nation talks on the North's nuclear programs that have been stalled since North Korea walked away from them in 2009. The talks involved North and South Korea, China, the U.S., Japan and Russia.

"The Chinese side opposes the imposition of sanctions taken outside the framework of the Security Council resolution 2321," Wu was quoted as saying by the foreign ministry.

As the North's chief source of aid and diplomatic support, China has reluctantly agreed to U.N. sanctions, but said they should be used sparingly as an inducement for the North to rejoin talks.

China demands that South Korea "give weight to China's concerns" about the Terminal High-Altitude Area Defense, or THAAD, missile system, which is intended to counter North Korea's nuclear and missile threats, Wu said, according to the ministry.

Russia also opposes the system, saying it could help the U.S. monitor its own missiles and other military developments.