There is "no known threat" on Capitol Hill at present, according to Senate Sergeant at Arms.
Capitol Hill, which houses both US legislative bodies and a number of other government buildings, is less than a mile from the Washington Navy Yard where the shooting occurred.
USCP continue to monitor #NavyYardShooting. At this time, no known threat to Capitol Hill, incident stays confined at Navy Yard.
Capitol Police continue monitoring active shooter at Navy Yard. At this time, incident confined to Navy Yard. No known Capitol Hill threat.
Capitol Police told NBC News that "enhanced security measures" are in place in the area.
Despite having serious mental health problems and previous incidents with firearms, Aaron Alexis held security clearance for the Navy base.
At least 13 people, including the suspected gunman, have been killed in a shooting at a Navy base in Washington DC.