A number of people are tweeting from the scene:
WASHINGTON (ABC7) — The U.S. Capitol is on lockdown Friday morning, ABC News confirms.
A number of people are tweeting from the scene, including the report from a Hill staff writer that someone with a gun got past security:
WASHINGTON (AP) — The U.S. Capitol building is on lockdown, with police barring people from entering.
The Senate seargant at arms issued a lockdown alert for the building and visitor center, saying police activity has been reported. Capitol office buildings are open.