North Korea must take steps towards verified denuclearization before achieving the "shared goal" of an official end to the 1950-53 Korean War, Stephen Biegun, U.S. Special Representative for North Korea, said during meeting with senior South Korean officials, CNBC reported.

The two diplomats sought to inject fresh momentum into stalled nuclear talks, with Biegun saying he was "absolutely certain" the allies could work together to achieve their objective of denuclearization.

"We have a shared goal here, which is to bring an end to 70 years of war and hostilities on the Korean peninsula," Biegun told Lee at the start of their meeting.

"And the primary requirement for us to get to the end point is to achieve final, fully, verified denuclearisation of North Korea. I am absolutely confident this is within reach."