Private Travis King, the American soldier who ran into North Korea in July, is in US custody and heading home after being expelled by North Korea into China, the US says.

While details about the diplomacy that led to King’s transfer remained scarce, the positive resolution of the case was a rare example of co-operation between the US, North Korea and China.

King, 23, made a sudden dash into North Korea from the South on July 18 while on a civilian tour of the Joint Security Area on the heavily fortified border between the neighbours. He was immediately taken into North Korean custody.

The incident triggered heated discussions inside the US government but its officials declined to declare him a prisoner of war.

For its part, North Korea appears to have treated his case as one of illegal immigration.

North Korea’s KCNA state news agency said King had been expelled after admitting to entering North Korea illegally because he was “disillusioned about unequal US society”.

North Korea’s decision, published by KCNA, detailed the final results of an investigation into King’s border crossing.

Last month, it reported interim findings that he wanted refuge in North Korea or elsewhere because of maltreatment and racial discrimination within the US army.

“King confessed that he illegally intruded into the territory of the DPRK as he harboured ill feeling against inhuman maltreatment and racial discrimination within the US army and was disillusioned about the unequal US society,” KCNA said.

DPRK refers to North’s official name, the Democratic People’s Republic of Korea.

US officials, citing US diplomatic representatives who saw King as he was departing China, said he appeared to be in good health and spirits and was “very happy” to be on his way home.

He was able to speak with his family after his release from North Korea.

His release followed months of intense diplomacy, the US officials said, adding that no concessions were made to the North in exchange for King.

The Swedish government retrieved King in North Korea and brought him over the border into China where he was taken into US custody, the US officials said, expressing their gratitude to both Sweden and China.

Sweden has been the “protecting power” in North Korea for the US, which has no diplomatic representation in the country.

“Ms Gates will be forever grateful to the United States army and all its interagency partners for a job well done,” Jonathan Franks, spokesman for King’s mother Claudine Gates, said.

King’s uncle Myron Gates told ABC News in August that his nephew, who is black, experienced racism during his military deployment and that after he spent time in a South Korean jail, he did not sound like himself.

King, who joined the US army in January 2021, faced two allegations of assault in South Korea.

He pleaded guilty to one instance of assault and destroying public property for damaging a police car during a profanity-laced tirade against Koreans, according to court documents.

He had been due to face more disciplinary measures when he arrived back in the US.

King had finished serving military detention and had been transported by the US military to the airport to return to his home unit in the US.

Instead, he left the airport and joined a tour of the border area, where he ran across despite attempts by South Korean and US guards to stop him.

One US official said the military would consider what administrative actions King might face after he was evaluated, taken through a reintegration process and reunited with his family in the US.

A different US official said King was heading to Brooke Army Medical Center in Texas, which is at Joint Base San Antonio-Fort Sam Houston.