North Korea says it will deport US soldier Travis King who ran across the border from South Korea during a tour in July.

Pyongyang will deport him having finished its investigation into King's "illegal" entry, state news agency KNCA said.

KCNA did not specify how, when or to where Private King would be expelled.

His release comes a month after North Korea acknowledged detaining the 23-year-old.

According to KCNA, he confessed to having illegally crossed into North Korea "due to inhuman treatment in the US military, antipathy to racism and disillusionment with the unequal US society."

"The relevant body in the Democratic People's Republic of Korea has decided to deport US soldier Travis King, who illegally entered the territory of the republic, in accordance with the laws of the republic," KCNA said.

No details have been given about Private King's state of health and he has not been heard from or seen since his crossing.

He was on a guided tour of the Demilitarised Zone (DMZ) that separates the two Koreas when he left the group and ran across the border.

Private King had previously served two months in detention in South Korea on assault charges before being released on 10 July.

He is a reconnaissance specialist who had been in the army since January 2021 and was in South Korea as part of his rotation.