China told a North Korean delegation last week that it wants to realize the goal of denuclearizing the Korean Peninsula, South Korea's top nuclear envoy said Wednesday after meeting with his Chinese counterpart.

Kim Hong-kyun, South Korea's Special Representative for Korean Peninsula Peace and Security Affairs, made the remarks after holding talks with Wu Dawei earlier in the day, during which the Chinese official briefed Kim on last week's visit by a top North Korean official, Ri Su-yong, to Beijing.

Chinese President Xi Jinping met Ri in an apparent bid to mend political ties that were strained by North Korea's nuclear weapons ambition.

Citing a conversation with Wu, Kim said, "When Ri Su-yong visited China, the Chinese side made clear its stance on the Korean Peninsula, including denuclearization of the Korean Peninsula."

Wu also told Kim that China is committed to fully enforcing U.N. sanctions against North Korea's nuclear and missile programs.

"The Chinese side voiced its strong opposition to North Korea's additional provocations, including more nuclear and missile tests," Kim said.

North Korea has been slapped with tougher U.N. sanctions following its fourth nuclear test in January.

Wrapping up high-level talks with Chinese counterparts on Tuesday, U.S. Secretary of State John Kerry told reporters in Beijing that China is determined to "fully enforce" U.N. sanctions against North Korea.

The meeting between Kim and Wu comes as the International Atomic Energy Agency warned earlier this week that North Korea appears to have restarted its main nuclear bomb fuel plant.

If the warning by the IAEA is correct, it would be the latest move by North Korea in expanding its nuclear weapons program, despite tightened international sanctions.

Kim said South Korea and the U.S. are closely monitoring the warning by the IAEA on North Korea's nuclear activities with "grave concern."

However, there was no discussion about the apparent restart of reprocessing spent nuclear fuel to produce plutonium at the Yongbyon nuclear complex during Wednesday's talks with Wu, Kim said. (Yonhap)