Police detained the driver of a box truck on Monday night after the vehicle crashed into security barriers on Lafayette Square adjacent to the White House grounds, a US Secret Service spokesperson said.
"There were no injuries to any Secret Service or White House personnel, and the cause and manner of the crash remain under investigation," Anthony Guglielmi, chief of communications for the US Secret Service, said on Twitter.
Some roads and pedestrian walkways were closed, the Secret Service said.
The nearby Hay Adams hotel was evacuated at the request of the Secret Service, the Washington Post reported, citing a hotel official.
WUSA television showed live video of a box-type, U-Haul truck stopped alongside a row of steel bollards, with uniformed law-enforcement officers and a dog approaching the vehicle. A remote-controlled robot pried open the truck's rear door, revealing a dolly but no other obvious cargo.
After crashing, the driver hit the barriers a second time, WUSA reported, citing a witness report.
A brief video posted on social media shows a U-Haul slamming into the barriers from a short distance for what the person posting it said was the second time. Reuters could not verify the authenticity of the video.
A spokesperson for the Washington Fire Department said a call came in at 9.40pm (0130 GMT) for what was described as a suspicious package investigation.
"All units are standing by to assist law enforcement for anything they need for their investigation," public information officer Vito Maggiolo said.
Washington Metro Police assisted other agencies at the scene, the Washington Post said, citing a police spokesman.