An American soldier was detained on charges of criminal misconduct in the Russian Far East city of Vladivostok last week while on leave after finishing his tour of duty in South Korea, officials said Monday.

US Army spokesperson Cynthia Smith said that the soldier, whose name was withheld, was detained Thursday, and that the US Army notified his family of his detention.

The soldier was on leave in Russia following the completion of his tour of service in South Korea, a US official told Yonhap News Agency. He was in the process of returning to the United States for his next assignment.

He is not absent without leave or AWOL, the unnamed official added.

"The Russian Federation notified the US Department of State of the criminal detention in accordance with the Vienna Convention on Consular Relations," Smith said in a statement.

"The Army notified his family and the US Department of State is providing appropriate consular support to the soldier in Russia," she added.

The soldier's detention comes as relations between Washington and Moscow have been frayed due to Russia's war against Ukraine and other issues.

White House Security Communications Adviser John Kirby said that he is aware of the case.

"I can't really say much about it right now. ... I hope you can understand that," he told a press briefing. "It's certainly a better question put to our DoD colleagues, but we are aware of this case."

DoD stands for the Department of Defense. (Yonhap)