Jose Luis Magana, Associated Press
Police officers direct the emergency response vehicles at the gates of the Walter Reed Medical Center in Bethesda, Md., Monday, July 6, 2015.

BETHESDA, Md. — Police say there's no evidence of gunshots and no injuries reported after officers searched a 20-story tower at the Walter Reed National Military Medical Center outside Washington.

Montgomery County police say a 911 call reporting hearing a single shot inside Building 1, part of the original hospital on the campus in Bethesda, came from the tower Monday morning.

Roads around the facility were closed for hours but are now open. Police and the Navy tweeted that all patient care at the facility has been suspended for the day.