Washington - A man fatally shot himself on the crowded pedestrian avenue directly in front of the White House on Saturday, officials said.

"Adult male has been declared deceased," the Washington, DC Police Department said on Twitter.

The Secret Service said a white male approached the fence north of the White House at about 11:46 am (1646 GMT), "removed a concealed handgun and fired several rounds, none of which appear at this time to have been directed towards the White House".

The man's identity is being withheld pending notification of kin, the Secret Service said in a statement.

While as many as 100 people - mostly tourists - were on Pennsylvania Avenue in front of the White House at the time, no one else was reported hurt, the Secret Service said.

Police and medical personnel quickly swarmed the area, and the White House was placed on lockdown.

The area north of the White House was cleared and cordoned off. Police also draped yellow crime-scene tape along a full block of nearby K Street, where authorities were searching a parked car.

At the time, President Donald Trump and first lady Melania were at his Mar-a-Lago resort in Florida. The president was set to return to Washington later Saturday to attend the annual Gridiron Club media dinner.

"We are aware of the incident," deputy press secretary Hogan Gidley said. "The president has been briefed."

Local police will lead an investigation of the shooting, with support from the Secret Service and other agencies, the Secret Service said.

Reporters in the White House briefing room first tweeted about the shooting, saying they had been told to shelter in place.

Disturbances outside the White House are not rare. On February 23, a woman was arrested after crashing her vehicle into a security barrier near the presidential residence.

And there have been repeated attempts to jump over fences around the building.