A man who set himself on fire in a part of Washington DC close to the US Capitol has died of his injuries.
Officer Araz Alali says the man died Friday night at a Washington hospital where he had been airlifted.
He added that the man was so badly burned that he will need to be identified through DNA and dental records.
Witnesses said they saw the man dump a canister of petrol over his head and then set himself on fire.
Witness Vanessa Sink wrote on Twitter: "Just witnessed the craziest thing ever ... a man set himself on fire and danced down the Mall.
The Independent reports that another witness Katy Scheflen said passing joggers took off their shirts to help douse the flames.
Ms Scheflen added he might have said something before he acted, "but it was nothing intelligible".
The incident happened just after 4.20pm EST (9.20pm UK time) on Friday in a part of Washington DC called the National Mall, between Capitol Hill and the White House.
It comes during a period of heightened tension in the capital, just weeks after 12 people were shot at the Washington Navy Yard.