A man has set himself on fire in a park outside the courthouse where Donald Trump's criminal trial is happening in New York. 

Journalists at the scene saw the man throw pamphlets in the air, before dousing himself in lighter fluid and setting himself on fire.

Emergency crews have rushed away a person on a stretcher after fire was extinguished outside the Manhattan courthouse where jury selection was taking place in Donald Trump’s hush money criminal case.

The man could be seen lying on the ground on fire. People rushed over to douse the man with a fire extinguisher and try to bat the flames away.

Emergency responders then took the man away on a stretcher. 

The New York Police Department said the man has been transported to a nearby hospital in a critical condition.

A full jury of 12 people and six alternatives had been selected in the hush money case just minutes earlier, drawing the first criminal trial of a former US president a step closer to opening statements.