STORY: A U.S. soldier detained in Russia traveled there while on leave despite a prohibition by the Department of Defense and State Department, the Pentagon said on Tuesday.

It says he traveled to Russia through China without military clearance.

Russian officials say the soldier, who the U.S. Army identified as Staff Sergeant Gordon Black, was arrested on charges of theft.

Black had been assigned to Camp Humphreys in South Korea most recently and was set to return to Texas.

Here's Pentagon spokesperson Sabrina Singh:

"Instead of returning to the U.S., Black flew from Korea through China and then to Vladivostok, Russia for personal reasons. As of right now, Black is currently in a pretrial detention facility. It's my understanding he will remain there until his next hearing and I'm not sure on that date. I'd refer you to State Department on that. The Army has opened an administrative investigation to determine the facts and the circumstances surrounding his travel."

The Army said the Russian interior ministry informed the U.S. on May 3 that Black had been arrested the day earlier for "theft of personal property."

The Russian interior ministry said a 32-year-old woman had filed a complaint against the 34-year-old suspect.

The two had met in South Korea, and Black came to Russia to visit her, the ministry said.

The two had an argument, and she later filed a police report accusing him of stealing money, it said.

Black was arrested in a local hotel, having bought a plane ticket to return home.

The Russian Foreign Ministry said the case had no political element and there were no allegations of espionage.