WASHINGTON, May 28 (NNN-Xinhua) -- Former U.S. Ambassador to South Korea Sung Kim on Sunday crossed into the Democratic People's Republic of Korea (DPRK)(North Korea) to talk about the preparation for a summit between leaders of the two countries, local report said.

Sung Kim, a former U.S. ambassador to South Korea and ex-nuclear negotiator, was summoned from his present posting as U.S. Ambassador to the Philippines to talk with Choe Son Hui, DPRK's vice foreign minister, the Washington Post said in a report.

Sung Kim came to meet with DPRK's Vice Foreign Minister Choe Son Hui, together with Allison Hooker, the U.S. National Security Council member, and Randall Schriver, the assistant secretary of defense for East Asia of State Department.

The Washington Post quoted State Department spokesperson Heather Nauert as saying that the meetings are expected to continue Monday and Tuesday in the northern part of the demilitarized zone where DPRK leader Kim Jong Un met with South Korean President Moon Jae-in on Saturday.

The two delegations will reportedly be focused on the substance of the summit between U.S. President Donald Trump and Kim -- the DPRK's nuclear weapon program.

The White House has not yet confirmed the report.

Just a day before, South Korean President Moon Jae-in and Kim Jong Un held a surprise meeting on the northern side of the border village Panmunjom, the second inter-Korean summit in a month.

Moon said Sunday that both Kim and Trump wished the success of their summit "wholeheartedly."

Trump also said on Saturday that Washington is "doing very well in terms of the summit with" Kim.

"A lot of people are working on it. It's moving along very nicely," he said. "We're looking at June 12th in Singapore. That hasn't changed. And it's moving along pretty well."

Trump canceled the scheduled meeting on Thursday, saying that it will not happen "based on the tremendous anger and open hostility" displayed in the DPRK's most recent statements.

However, he reversed course just one day after the announcement. Both sides wanted the meeting to happen and it could still go ahead after productive talks, he said.

A White House spokeswoman said on Saturday that a White House team will leave as scheduled for Singapore this weekend to prepare for the Trump-Kim talks.--NNN-XINHUA

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