The FBI said in a statement its Washington Field Office is responding and providing support to Capitol Police. He exited the vehicle and began "lunging" toward police with a knife visible in his hand, at which point officers fired their weapons, killing the suspect.
The officials initially said the suspect was being taken to the hospital in critical condition.
The suspect's name has not been released, but he died at a hospital.
The man was reportedly shot while trying to launch an attack.
He said the attack was not believed to be related to terrorism.
But Congress is now in recess, meaning the majority of politicians are not at the Capitol complex today.
One person has died after slamming a vehicle into the security barrier surrounding the Capitol building, U.S. media report.
The security checkpoint is typically used by senators and staff on weekdays, but lawmakers are away on break.
Congress is in recess today and staff I have spoken to are grateful to be home and nervous about returning to work after the Easter holiday.
This time, one officer was killed and a second hospitalized after a driver rammed a security checkpoint on the Capitol grounds.
Television footage showed a blue sedan crashed into a security barrier on one of the streets leading to Congress, as what appeared to be the injured officers were loaded onto gurneys and into ambulances.