Washington, D.C., and Alexandria and Arlington in Virginia are under a curfew until 6 a.m. Thursday.
As of 10:30 p.m., D.C. police reported 47 arrests of curfew violators.
Mayor Muriel Bowser announced D.C.'s curfew Wednesday afternoon after a mob rushed up the steps of the U.S. Capitol as Congress debated the presidential vote count. Rioters then breached the Capitol building.
Late Wednesday Bowser extended a public emergency declared earlier Wednesday for 15 days.
A woman died after being shot by law enforcement at the Capitol, sources told NBC News. A woman and two men died after suffering medical emergencies around the Capitol grounds, D.C. police said. Their causes of death will be determined by the Office of the Medical Examiner.
Virginia Gov. Ralph Northam also ordered a curfew for the City of Alexandria and Arlington County in Washington's suburbs.
“We know that a lot of these individuals were going to come right across the Potomac River and stay in Arlington and Alexandria, and I talked to leadership in both of those areas, and we don’t want any more trouble tonight, or for that matter, any day, and so we invoked a curfew for Alexandria and Arlington ,” Northam told News4.
D.C.'s curfew was announced over a loudspeaker at the U.S. Capitol when it went into effect at 6 p.m.
Photos: Pro-Trump Supporters Breach the Capitol Building
Officials declared the U.S. Capitol complex “secure” about 6 p.m. after heavily armed police moved to end a violent, nearly four-hour occupation.
Some of the mob remained in the streets around the Capitol after the curfew went into effect but began to disperse. Police and the National Guard are attempting to clear the streets and enforce the curfew, moving the crowd back a block or half-block at a time every couple of minutes. By 7 p.m., the majority of the crowd had left.
“Today what we witnessed was riotous and unlawful behavior,” Metropolitan Police Department Chief Robert Contee said.
“I continue to urge all Washingtonians to stay home and stay calm, and if you see something, say something,” Bowser said in an address to the city. “But above all, stay home."
“If you are found to be in violation of the curfew, police will be required to take action,” Contee said.
“During the hours of the curfew, no person, other than persons designated by the Mayor, shall walk, bike, run, loiter, stand, or motor by car or other mode of transport upon any street, alley, park, or other public place within the District,” the mayor’s office said in a statement.
The order does not apply to essential workers, including members of the media, who are working or traveling to or from work.
WMATA announced all Metrorail and Metrobus service will end early Wednesday "in the interest of public safety." The Metrorail system is closing three hours early at 8 p.m., while Metrobus service ends at 9 p.m.
The last trains will leave downtown transfer stations at 8 p.m., and service toward downtown will end earlier. There will be no alternate transportation.
Buses scheduled to begin service at 9 p.m. or later will not run. Buses already in service at that time will continue operating to the end of the line before going out of service.
MetroAccess will not begin any new trips after 9 p.m. Customers with reservations will be contacted.
Additional service adjustments will be announced if necessary.
George Washington University men's basketball's game against the University of Massachusetts has been postponed due to the curfew and will be rescheduled for a later date.
Stay with NBC Washington for more details on this developing story.