The United States and North Korea have set up working groups to discuss ways to rid Pyongyang of its nuclear weapons, a U.S. official said Saturday, the second day of a two-day trip to Pyongyang by Secretary of State Mike Pompeo.

The working groups will deal with details such as verification to achieve denuclearization, State Department spokeswoman Heather Nauert said, according to a pool report by U.S. reporters accompanying Pompeo.

(Kim Yong Chol at Beijing airport on June 4, 2018)

Pompeo held three hours of talks Friday with Kim Yong Chol, a vice chairman of the Central Committee of the Workers' Party of Korea, to nail down specifics about the commitment to "complete" denuclearization that the North's leader Kim Jong Un made during a historic summit with U.S. President Donald Trump last month in Singapore.

Pompeo and Kim Yong Chol, a close aide to leader Kim, also discussed the repatriation of the remains of American troops who died in the 1950-1953 Korean War, Nauert was quoted by the pool report as saying.

The two sides continued negotiations Saturday, Nauert said in a Twitter post.

The White House has said Pompeo would be meeting with Kim Jong Un, but it was not known whether the meeting had taken place.

The chief U.S. diplomat met with the North's leader on his two trips to Pyongyang in recent months that paved the way for the first-ever U.S.-North Korea summit on June 12.

After leaving Pyongyang later Saturday, Pompeo will visit Tokyo for a trilateral meeting Sunday with Japanese Foreign Minister Taro Kono and South Korean Foreign Minister Kang Kyung Wha on coordinated action over North Korea.