US Capitol Police say all Capitol buildings were being locked down "due to an external security threat" and staff members were told they could not enter or exit the buildings.
The Capitol Building was placed on lockdown Friday after a knife-wielding suspect who has since died in the hospital - identified as 25-year-old Noah Green - rammed his auto into the North barricade, killing Evans and injuring another Capitol officer.
"U.S. Capitol Police officers fired upon him".
But Congress is now in recess, meaning the majority of politicians are not at the Capitol complex today.
Friday's incident left at least one officer dead and another officer injured.
The death is the latest moment of sorrow for a department after the loss of Brian Sicknick, who clashed with rioters during the January 6 insurrection and died a day later, and Howard Liebengood, who committed suicide weeks after that.
US Capitol On Lockdown After Vehicle Rams 2 Officials, Driver Dead
The law enforcement officials told the AP that the suspect was shot and was being taken to the hospital in critical condition. The US Capitol complex was placed on lockdown after the shooting and staff were told they could not enter or exit buildings.
Authorities have begun only in the past couple of weeks to remove the outer ring of high, razor-wire-topped fencing erected around the Capitol complex after the January 6 insurrection by thousands of supporters of then-president Donald Trump.
A statement from the Washington, D.C., Metropolitan Police Department said: "A call came in at approximately 1:05 pm to the unit block of Constitution Ave, NE, for the report of a possible shooting".
Both Capitol Police officers and the driver were taken to the hospital, the officials said. Authorities shot the suspect, identified by law enforcement officials as 25-year-old Noah Green.
The incident occurred about 100 yards (91 meters) from the entrance of the building on the Senate side of the Capitol, which is typically used by senators and staff on weekdays.
Video posted online showed a dark-coloured sedan crashed against a vehicle barrier and a police dog inspecting the vehicle. House Speaker Nancy Pelosi hailed Evans as a "martyr for our democracy", while Senate Majority Leader Chuck Schumer said he was "heartbroken".
Biden had just departed the White House for Camp David when the attack occurred.
The National Guard mobilized under the presumption that an attack could be ongoing.