A man went up in flames in the middle of the National Mall on Friday before bystanders extinguished the fire and he was rushed to a hospital, police and witnesses said.
Initial reports indicated the man set himself on fire, though it could not yet be confirmed, police spokesman Hugh Carew said.
The man was hospitalized in critical condition, Mitch Smith of the National Park Police told Reuters.
Police responded to an emergency call about a fire shortly before 4:30 p.m. on the Mall lined by Washington's famed Smithsonian museums, authorities said.
"Officers and citizens extinguished the flames," Smith said.
Nicole Didyk, an environmental engineer for the Federal Aviation Administration, told Reuters she was out for a run when she saw spotted a man with small flames on him.
"He was the only one in the middle of the mall," she said. "There were five gentlemen hitting him with their T-shirts. When he fell over his arms were all white. He was burnt really bad."
The man thanked people who helped put the fire out, Didyk said.
She said the incident occurred on the grassy part of the Mall several blocks from the Capitol grounds, where a day earlier a car chase that began near the White House ended in a fatal shooting.
Carew said the man was still conscious and breathing when he was taken to the hospital.
There was a red plastic gas cannister on the grass near where the man had been.