A man who fired 15 to 20 shots with an assault-type rifle at the federal courthouse in Wheeling, W.Va., on Wednesday was shot and critically wounded by security officers, The Associated Press reported.

The U.S. Marshals Service told the wire service that one officer was injured by shattered glass in the courthouse, but there were no other injuries.

Chief Deputy Mike Claxton of the Marshals Service told the AP that the shooter was in a parking lot across from the courthouse. His motive was not known.