WASHINGTON — The police on Monday shot a man who pointed a gun at them in a screening area just outside the United States Capitol, briefly unnerving the city a week after the bombings in Brussels.

As the scene unfolded in the entrance to the Capitol Visitor Center and law enforcement officials swept the Capitol complex, employees and visitors inside were forced to stay in place for almost an hour. Others who were on the grounds were asked to evacuate as the police cordoned off the site and nearby streets.

The man, identified by the police as Larry R. Dawson of Tennessee, and a female bystander who suffered minor injuries were taken to a nearby hospital, law enforcement officials said. Mr. Dawson was in stable but critical condition, according to the authorities.

Law enforcement officials quickly ruled out terrorism, saying that they were convinced that Mr. Dawson had acted alone. “There is no reason to believe that this is anything more than a criminal act,” said Chief Matthew Verderosa of the United States Capitol Police.