Tillerson overture to N.Korea: U.S. ready to talk without pre-conditions

(Adds U.N. diplomat, paragraphs 7-10)

By David Brunnstrom and Matt Spetalnick

WASHINGTON, Dec 12 (Reuters) - U.S. Secretary of State Rex Tillerson offered on Tuesday to begin direct talks with North Korea without pre-conditions, backing away from a key U.S. demand that Pyongyang must first accept that any negotiations would have to be about giving up its nuclear arsenal.

"Let's just meet," Tillerson told Washington's Atlantic Council think tank, presenting a new diplomatic overture amid heightened tensions over North Korea's nuclear and missile advances and harsh rhetoric between the two sides.

The White House later issued an ambiguous statement that left unclear whether President Donald Trump - who has said in the past that Tillerson was wasting his time pursuing dialogue with North Korea - had given his approval for the speech.

"The president's views on North Korea have not changed," the White House said. "North Korea is acting in an unsafe way. ... North Korea's actions are not good for anyone and certainly not good for North Korea."

The apparent shift in Tillerson's thinking came nearly two weeks after North Korea said it had successfully tested a new intercontinental ballistic missile in what it called a "breakthrough" that put the United States mainland within range.

While reiterating that Washington cannot accept a nuclear-armed North Korea, Tillerson said the United States was "ready to talk any time they're ready to talk." But he insisted there would have to be a “period of quiet” without nuclear and missile tests to have productive discussions.

At the United Nations, a senior U.N. official said after returning from a visit to North Korea that senior North Korean officials had not offered any commitment to talks when he was there last week, but he believed he left "the door ajar."

U.N. political affairs chief Jeffrey Feltman, a former U.S. State Department official, was the highest-level U.N. official to visit North Korea since 2011 and met with Foreign Minister Ri Yong Ho and Vice Minister Pak Myong Guk during a four-day visit he called "the most important mission I have ever undertaken."

"Time will tell what was the impact of our discussions, but I think we have left the door ajar and I fervently hope that the door to a negotiated solution will now be opened wide," Feltman told reporters after briefing the U.N. Security Council behind closed doors on his visit.

"They need time to digest and consider how they will respond to our message," he said.

In his remarks, Tillerson also disclosed that the United States had been talking to China about how to secure North Korea’s nuclear weapons in the event of a collapse of the government in Pyongyang. Washington had given Beijing assurances that if U.S. forces ever had to cross into North Korea they would not stay there and would return across the border into South Korea.