U.S. military personnel fired shots on Monday as they stopped a man who tried to force his way onto a British military base used by the U.S. Air Force, in an incident that police said was not being treated as terrorism.

The Mildenhall Royal Air Force base said security staff locked down the base, used by the United States military to refuel U.S. and NATO aircraft in Europe, at about 1300 GMT following reports of a disturbance.

"Shots were fired by American service personnel and a man has been detained with cuts and bruises and taken into custody," Suffolk police said. "No other people have been injured as a result of the incident."