"We remain in regular contact with the North Koreans, and progress was made at the Hanoi Summit. Yes, we did not reach the agreement but, at the same time, we were able to exchange very detailed positions, and that has narrowed the gap on a number of issues," Palladino told reporters on Tuesday.

The United States would like to move forward with the denuclearization of the Korean peninsula and build on the momentum of the progress achieved at the summit, he added.

The long-anticipated second summit of US President Donald Trump and North Korean leader Kim Jong Un was held in the Vietnamese capital last week.

Trump walked away from the talks on their second day after the Kim demanded that all sanctions be lifted in exchange for denuclearization, but not in the areas Washington wanted.  

Image: The White House Twitter page