US ready to negotiate with N Korea 'immediately': Pompeo

US Secretary of State Mike Pompeo welcomed Pyongyang's "important commitments" made by Pyongyang during Wednesday's inter-Korean summit, adding Washington was ready to begin negotiating immediately to achieve the denuclearisation of North Korea "by January 2021".

In a statement, Pompeo said he spoke with his North Korean counterpart Wednesday morning and invited him to meet in New York next week on the sidelines of the United Nations General Assembly.

The statement came after the North's leader Kim Jong Un agreed to make a historic visit to Seoul soon and close a missile testing site in front of international inspectors in a meeting with the South's President Moon Jae-in.

Progress on the key issue of the North's nuclear arsenal was limited, but the two signed a document to strengthen ties between the two halves of the divided peninsula.

Building on a growing rapprochement, they agreed to create a facility to hold family reunions at any time, work towards joining up road and rail links, and mount a combined bid for the 2032 Olympics.

"On the basis of these important commitments, the United States is prepared to engage immediately in negotiations to transform US-DPRK relations," said Pompeo.

In addition to Pompeo's meeting with North Korean Foreign Minister Ri Yong Ho, "we have invited North Korean representatives to meet our Special Representative for North Korea, Stephen Biegun, in Vienna, Austria at the earliest opportunity," the statement continued.

"This will mark the beginning of negotiations to transform US-DPRK relations through the process of rapid denuclearization of North Korea, to be completed by January 2021, as committed by Chairman Kim, and to construct a lasting and stable peace regime on the Korean Peninsula."