WASHINGTON, Sep 27 (AFP) - The United States said Wednesday that it did not see any diplomatic breakthrough with North Korea over the return of a US soldier, seeing the episode as isolated.

"I would not see this as a sign of some breakthrough. I think it's a one-off," State Department spokesman Matthew Miller told reporters.

"We are open to diplomacy with North Korea, we would welcome diplomacy with North Korea; they have always rejected that," he said.

Miller condemned comments a day earlier at the United Nations by North Korea's representative who accused the United States of pushing the Korean peninsula "closer to the brink of nuclear war."

"We would obviously find those remarks irresponsible, as we find any number of statements that North Korea makes threatening its neighbors or raising tensions in the region," he said.

Miller confirmed that King was on his way back to the United States after a stop in Osan military base in South Korea.

He was transported out of North Korea to China, flying from the border city of Dandong to Shenyang, where King was greeted by the US ambassador to China, Nicholas Burns.

In the United States, King will be taken to the Brooke Army Medical Center in Texas, another US official said.

Photo from AFP