The Washington Post, citing a person familiar with the arrangements, said Sung Kim, a former U.S. ambassador to South Korea and former nuclear negotiator with the North, was leading the preparations on the U.S. side.

A team of U.S. officials crossed into North Korea on Sunday for talks to prepare for a summit between President Trump and Kim Jong Un, as both sides press ahead with arrangements despite the question marks hanging over the meeting.

Sung Kim, a former U.S. ambassador to South Korea and former nuclear negotiator with the North, has been called in from his post as envoy to the Philippines to lead the preparations, according to a person familiar with the arrangements.