U.S. Capitol Police spokeswoman Sgt. Kimberly Schneider says officers were told around 5 a.m. Friday to be on the lookout for a man with a gun.
Officers later saw the man, who pointed the gun at them. Schneider says the officers opened fire after the man refused to drop his weapon and that officers fired because they were in "fear for their lives."
The man, whose name has not been released, was brought to a hospital. His condition is not immediately known.
No other injuries were reported.
Schneider says the Metropolitan Police Department is assisting with the investigation.