Nobody was injured, but the incident rattled leaders in the town of Grafenwöhr, which has a population of about 6,600.
“I was worried about the city, but fortunately nothing serious happened," deputy Mayor Udo Greim told the Süddeutsche Zeitung. The newspaper reported that there have been similar incidents three or four times over the past 25 years.
In a statement, the US Army said the bullets came from 12.7-millimetre rounds fired by a machine gun mounted on a Humvee. They hit several buildings, including a vocational school and residential building.
It added that US military and German police were looking into what happened and how such incidents can be prevented.
In the statement, Lt. Col. Scott Moore said the Americans had launched an “intensive review of security procedures and standards.”
“The security of the military site Grafenwöhr and the surrounding cities and towns are the main focus of the US Joint Multinational Training Command,” said Moore.
An army spokesman, Franz Zeilmann, told The Local that officials were very sorry and grateful that no one was hurt.
“It shouldn't have happened,” he said. “We take this very seriously.”
US military accidents occur periodically, though are rarely pose a danger to civilians. Last year a Black Hawk helicopter crashed near a Mannheim motorway killing three soldiers, though no civilians were hurt.
Ten years ago, an elementary school near the Grafenwöhr installation was hit by a shell during training.