FILE - In this Dec. 15, 2017, file photo, U.S. special envoy for North Korea policy Joseph Yun, speaks to media in Bangkok, Thailand. Yun, the 30-year veteran of the U.S. foreign service who retained quiet contacts with North Korea amid the Trump administration’s turbulent first year, is retiring as Washington and Pyongyang step up considerations for formal diplomatic talks. Yun told The Associated Press he will stand down as special representative for North Korean policy on Friday. (AP Photo/Krit Phromsakla Nasakolnakorn, File)

WASHINGTON - Joseph Yun, a 30-year veteran of the U.S. foreign service who retained quiet contacts with North Korea amid the Trump administration's turbulent first year, is retiring as Washington and Pyongyang step up considerations for formal diplomatic talks.

Yun told The Associated Press he will stand down as special representative for North Korean policy on Friday. He said his decision to retire is entirely his own but it comes at a surprising juncture, just after American ally South Korea relayed that the North is open to direct discussions with the United States. His departure will leave the Trump administration without an envoy for engaging North Korea or an ambassador in South Korea.

Yun, a former U.S. ambassador to Malaysia, has been the State Department's point man for its limited contact with the North Korean government through a back channel at the U.S. diplomatic mission to the United Nations in New York. The adversaries from the Korean War don't have formal relations, and the so-called "New York channel" is the primary means for conveying messages between the two governments.

"One of my accomplishments has been to open the New York channel soon after the Trump administration got in," Yun told the AP. "That allowed for direct talks and direct communication. Really, there is no problem with communicating. It's problems of engagement that have been difficult."

Yun visited Pyongyang in June to secure the release of U.S. college student Otto Warmbier, who had been imprisoned for 17 months for stealing a propaganda poster. Warmbier died days after his repatriation. Yun has been frustrated by North Korea's reluctance to release the remaining Americans held in North Korea and discuss its nuclear weapons program, which President Donald Trump has threatened to dismantle by force, if necessary.

State Department spokeswoman Heather Nauert said Yun retired for personal reasons, which the diplomat confirmed. Secretary of State Rex Tillerson "has reluctantly accepted his decision and wished him well," Nauert said.

"We are sorry to see him retire, but our diplomatic efforts regarding North Korea will continue based on our maximum pressure campaign to isolate the DPRK until it agrees to begin credible talks toward a denuclearized Korean peninsula," Nauert said, using the initials of the North's official name. After first suggesting he might not be replaced, Nauert sent a statement to reporters saying someone would fill Yun's position.

Yun's immediate departure will add to a shortage of top diplomats handling Korean policy. The ambassador post in South Korea has been vacant for the past year, adding to questions about the direction of U.S. policy as Trump has vacillated between talk of war and willingness to speak directly with leader Kim Jong Un.

A rapprochement between the two Koreas, inspired by South Korea's recent hosting of the Winter Olympics, offers a glimmer of hope for diplomacy. During Sunday's closing ceremony for the Olympics Games, the office of South Korean President Moon Jae-in reported that a North Korean delegate to the Olympics said his country has "ample intentions of holding talks with the United States."

Experts described Yun as one of the few U.S. officials with experience dealing at a senior level with North Korea. They predicted his departure will add to doubts about U.S. willingness to conduct diplomacy with Pyongyang, while compounding the depletion of the State Department's top ranks since Trump took office.

"Although U.S. strategy is supposedly maximum pressure 'and engagement,' Joe Yun was the only one seriously trying engagement," said Mark Fitzpatrick at the International Institute for Strategic Studies think-tank . "He is joining a large exodus of senior State Department officials who will be hard to replace."

Trump, who has threatened military force against North Korea in sometimes colorful tones, is determined to stop Kim's government from perfecting a nuclear-tipped missile that can strike the U.S. mainland. On Monday, Trump responded to the North's reported overture by saying talks will happen only "under the right conditions."

The North hasn't tested a nuclear device or ballistic missile for months. But the U.S. has pressed on with ever tougher sanctions, including a new set on the North's shipping capabilities. Trump warned last week that if sanctions fail, the U.S. would move to "phase two" in its pressure campaign, which could be "very rough" and "very unfortunate for the world."

News from © The Associated Press, 2018