The top nuclear envoys of South Korea and the United States held talks Sunday ahead of working-level negotiations between Washington and Pyongyang over a second summit between their leaders slated for late this month, Seoul's foreign ministry said.

Axar.az reports citing Yonhap.

Lee Do-hoon, the special representative for Korean Peninsula and security affairs, met his US counterpart, Stephen Biegun, hours after the latter arrived here for the meeting with his new dialogue partner, Kim Hyok-Chol, apparently later this week.

The ministry said that the two discussed the upcoming negotiations with Pyongyang aimed at fine-tuning details, including the agenda, for the summit between US President Donald Trump and North Korean leader Kim Jong-un.

Biegun and Kim Hyok-Chol are expected to meet on Tuesday at the inter-Korean border village of Panmunjom or in the North's capital of Pyongyang.

On Monday, the US envoy plans to visit the presidential office Cheong Wa Dae for a meeting with Chung Eui-young, the national security advisor.

Trump said that a date and venue for his summit with Kim will be announced this week. The summit will be held in late February, with Vietnam cited as the most likely venue.

This week, Washington and Pyongyang are expected to discuss details of the denuclearization steps that the North should take and corresponding measures from the United States.

The ministry indicated that Lee and Biegun will meet again after the working-level talks with North Korea.

They plan to have "constant, additional discussions" going forward, it said.

During Secretary of State Mike Pompeo's October trip to Pyongyang, the North's leader promised that the regime would dismantle and destroy all of its plutonium and uranium enrichment facilities in exchange for corresponding US measures, Biegun said during a speech at Stanford University last week.

Trump and Kim held their historic first summit in Singapore in June last year and agreed to work toward complete denuclearization of the Korean Peninsula in exchange for security guarantees for Pyongyang.

But the denuclearization talks had been at an impasse, with the North calling for sanctions relief and corresponding measures by the US for the denuclearization steps that it has taken so far, such as the dismantling of a nuclear test site.

Washington, however, has insisted that sanctions and pressure will be maintained until North Korea implements sincere denuclearization measures, including declaring a list of its nuclear weapons.

Biegun said last week that the North's full declaration of its nuclear and missile programs will be required for its complete denuclearization.