"The two sides reaffirmed their shared resolve to achieving the final, fully verified denuclearization of the DPRK, as agreed to by Chairman Kim in Singapore," department spokeswoman Heather Nauert said in a statement, using the North's official name, the Democratic People's Republic of Korea.

"The United States and China remain unified on our pressure campaign, and are committed to a bright future for the DPRK if Pyongyang denuclearizes quickly," she added, referring to a commitment to keep sanctions on North Korea until it denuclearizes.

Pompeo made his fourth trip to Pyongyang Sunday to press progress on an agreement reached between North Korean leader Kim Jong-un and US President Donald Trump at their first summit in Singapore in June.

Kim had committed to work toward "complete" denuclearization of the Korean Peninsula in exchange for security guarantees from the US.

Speaking in Seoul after the trip to Pyongyang, Pompeo said he had "good, productive conversations" with the North Korean leader on the steps to denuclearization and planning for a second summit between Kim and Trump.

He also said Kim had promised to let foreign inspectors in to verify last May's dismantlement of the North's key nuclear test site in Punggye-ri as soon as the logistics are worked out.

Pompeo and the Chinese leaders also discussed the bilateral relationship, including disagreements on sovereignty issues in the South China Sea and human rights, Nauert said. (Yonhap)