A U.S. soldier who officials say was entrusted with sensitive information has been arrested in the United Kingdom on suspicion of spying for Russia, according to British and U.S. officials.

The soldier was arrested Tuesday near Gloucester as part of a Counter Terrorism Policing investigation, the Metropolitan Police said.

Gen. Sean Stinchon, who leads U.S. Army Counterintelligence Command, described the man as a "senior soldier," saying in a statement that the arrest is "a sobering reminder that insider threats are real and persistent." Lt. Col. Brandon Carroll Tyner, 41, is the accused soldier being investigated, ABC News learned.