The 23-year-old's release comes after intense behind-the-scenes diplomacy and ends the prospect of a long stay in a country with a history of using detained Americans as bargaining chips.

North Korea's state news agency had made a surprise announcement just hours earlier that Pyongyang had decided to expel King, whom US officials said was in "good health."

King crossed the North Korean border to China with the help of Swedish diplomats, where he was handed over to the US ambassador and a senior miliary officer on Wednesday. He then flew out to a US miliary base.

"We can confirm that Private King was very happy to be on his way home," a senior US administration official told reporters. "He is very much looking forward to seeing his family."

After a drunken pub fight, an incident with police and a stay in South Korean jail, Private Second Class King was being taken to the airport in July to fly back to Texas.

But instead of travelling to Fort Bliss for disciplinary hearings, King snuck away, joined a Demilitarized Zone sightseeing trip and slipped over the border.

Last month, Pyongyang confirmed it was holding him, saying King had defected to North Korea to escape "mistreatment and racial discrimination in the US Army."

- 'Good place' -

But after completing its investigation, Pyongyang has "decided to expel Travis King, a soldier of the US Army who illegally intruded into the territory of the DPRK, under the law of the Republic," the Korean Central News Agency said Wednesday, using the North's formal acronym.

White House National Security Adviser Jake Sullivan said in a statement that "US officials have secured the return of Private Travis King" from North Korea.

"We thank the government of Sweden for its diplomatic role... and the government of the People's Republic of China for its assistance in facilitating the transit of Private King," he said.

King will be taken to the Brooke Army Medical Center in Texas upon his return to the United States -- the same place that US basketball star Brittney Griner was evaluated after being released by Russia.

"We're going to guide him through a reintegration process that will address any medical and emotional concerns and ensure we get him in a good place to reunite with his family," said a second official.

Any disciplinary action including a possible court martial would happen after that, the official added.

- 'One-off' -

King's border crossing came with relations between the two Koreas at one of their lowest points ever, with diplomacy stalled and North Korean leader Kim Jong Un calling for increased weapons development, including tactical nuclear warheads.

But the United States learned through Sweden earlier this month that North Korea wanted to release King, sparking frantic diplomatic efforts to secure his return home, the officials said.

China did not mediate with North Korea for King's release and the United States made no concessions "full stop" to Pyongyang, a senior administration official said.

US State Department spokesman Mathew Miller warned that King's release was a "one-off" and was not a sign of a "breakthrough" in ties with nuclear-armed North Korea.

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

The two Koreas remain technically at war because the 1950-53 conflict ended in an armistice, not a treaty, and most of the border between them is heavily fortified.

Pyongyang has previously used detained US citizens as bargaining chips in bilateral negotiations.

One of the last US citizens to be detained by the North was student Otto Warmbier, who was held for a year and a half before being released in a coma to the United States. He died six days later.

Around half a dozen American soldiers made rare defections to the North after the Korean War and were used for the country's propaganda.

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