President Donald Trump says his relationship with North Korea's Kim Jong Un is "very good," despite the collapse of the two leaders' summit in Hanoi, Vietnam.

A day after returning to Washington, Trump said on Twitter Friday that the two had "very substantive negotiations." He added, "We know what they want and they know what we must have."

Trump did not address the pushback from North Korea, which disputed his account of why the summit fell apart. Trump had told reporters the summit failed because Kim insisted that all the sanctions on Pyongyang be lifted without the North committing to eliminate its nuclear arsenal.

North Korea disputed that, insisting it asked only for partial sanctions relief in exchange for closing its main nuclear complex.