NBC News reported the incident occurred about 4:30 p.m. EDT near the Air and Space Museum.
Park Police told NBC Washington a man may have set himself on fire at the National Mall in Washington Friday afternoon.
Some joggers passing by took off their shirts and used them to try to put out the fire, NBC said.
Washington metro police told the Talking Points Memo website the man was "conscious and breathing" and had been airlifted to a hospital.
There was no word on the man's condition or identity.