BEIJING (Yonhap) -- China is open to three-way talks with South Korea and the United States on implementing new U.N. sanctions targeting North Korea's nuclear and missile programs, South Korea’s chief nuclear envoy said Saturday after meeting with his Chinese counterpart.

Kim Hong-kyun, South Korea‘s special representative for Korean Peninsula peace and security affairs, also said he and his Chinese counterpart, Wu Dawei, shared “concerns” about North Korea’s test-launch of two mid-range ballistic missiles a day ago.

Earlier this month, the U.N. Security Council levied tougher sanctions against North Korea’s fourth nuclear test on Jan. 6 and the Feb. 7 launch of a long-range rocket, both of which violated previous U.N. resolutions.

North Korea has remained defiant of U.N. resolutions, threatening to launch a nuclear strike on South Korea and the U.S. as well as a nuclear warhead test and ballistic missile launches.

“In order to cooperate on the process of implementing U.N. resolutions, we proposed holding a three-way consultation among South Korea, the U.S. and China,” Kim told a group of South Korean correspondents in Beijing.

“In response, the Chinese side said it will review the proposal in an open-minded manner,” Kim said.

South Korea and China agreed that, “North Korea must not take further actions that violate U.N. resolutions.”

“By earnestly implementing the U.N. resolutions, both sides agreed that it is important (for relevant countries) to create a situation where North Korea has no choice but to change its course,” Kim said.

In New York on Friday, the U.N. Security Council strongly condemned North Korea over the latest ballistic missile launches.

In a statement backed by China, North Korea’s diplomatic and economic lifeline, the Security Council said the North Korean missile launches were “unacceptable.”

China, which accounts for about 90 percent of North Korea’s total external trade, should play a key role in ensuring the effectiveness of U.N. sanctions on Pyongyang. 

A senior South Korean diplomat, who attended the Friday talks with Wu, told reporters that the two sides exchanged “more opinions” on holding three-way talks with the U.S. on implementing the U.N. sanctions on North Korea.

A U.S. website monitoring North Korea said the North’s nuclear test site is believed to be capable of supporting additional tests at any time, citing satellite imagery showing continued activity at the site.

The website 38 North said that the activity at the Punggye-ri underground test site does not appear directed at further tunnel excavation but rather to maintain existing tunnels as well as to clean up after the January nuclear test.

Asked about whether Kim and Wu exchanged views on the possibility of more nuclear tests by North Korea, the senior diplomat replied, “The two sides agreed that they should strongly warn North Korea against making further provocations.”

Analysts say that the North is expected to continue threats and provocations as Kim tries to assert his leadership in the lead-up to a key Workers‘ Party Congress in May.

China’s proposal of pursuing peace treaty talks with North Korea in tandem with denuclearization was one of topics during the talks between Kim and Wu, according to the senior diplomat.

“It is time to focus on sanctions and pressure on North Korea. It is too early to say about dialogue with North Korea at a time when North Korea refused to discuss denuclearization and defied U.N. resolutions,” Kim was quoted by the senior diplomat as telling Wu.

Wu told Kim that China understands the current situation and Beijing does not expect any dialogue with North Korea to take place anytime soon, according to the diplomat.

Signing a peace treaty, which would replace the armistice that halted the 1950-53 Korean War, has been one of Pyongyang‘s long-running goals, but South Korea and the U.S. have demanded the North abandon its nuclear program first.