The White House has been put on lockdown after a person was shot outside.
Secret Service officers shot an armed man outside the west of the White House after he brandished a weapon, a law enforcement source told CNN.
Visitors wrote on Twitter that they saw 'lots of people with guns' after shots were heard.
President Obama was not in the White House at the time as he was out playing a round of golf, while Vice President Joe Biden was rushed to a secure area of the building.
The shooting took place on 17th and E Streets - one block away from the White House - at around 2pm, the United States Park Police said.
DC Fire and EMS tweeted that one person was taken to hospital in a critical condition.
A suspect has been taken into custody, law enforcement officials told CNN.
President Obama reportedly left the White House shortly after 1pm for a round of golf at Andrews Air Force Base with three of his aides. He arrived there at about 1.30pm.
Vice President Joe Biden was taken to a secure area of the White House.
Secret Service officers were seen clearing the area and snipers were seen on the roof of the building.
Press at the White House were told to 'shelter in place'.