UPDATE 1-U.S., North Korea to seek understanding on denuclearization at summit

The United States and North Korea will seek a common understanding of what denuclearization means when President Donald Trump presses Kim Jong Un next week to give up all of the North's nuclear weapons, U.S. officials said on Thursday. Trump and Kim are set to meet in Vietnam for their second summit in an effort to thaw relations between the former foes and reduce one of the world's biggest nuclear threats.

U.S. officials have downplayed expectations for the meeting, and Trump has made clear he does not expect this one to be his last with Kim, a dictator he once derided as "little rocket man" but now considers a partner with whom he works well. Critics have said Trump gave Kim too much simply by meeting with him in Singapore last year. That criticism may be levied again for the Vietnam summit.

But the U.S. officials said the United States remained focused on getting the North Korean leader to denuclearize, even if he had not made that decision himself so far. "I don't know if North Korea has made the choice yet to denuclearize, but the reason why we're engaged in this is because we believe there is a possibility," one official said.

The two sides have not agreed previously on what denuclearization means. (Additional reporting by David Brunnstrom and Susan Heavey Editing by James Dalgleish)