Arsonists set off fireworks in Phoenix Walmart

US police are hunting for a group of arsonists after fireworks were set off inside a supermarket, igniting a blaze not far from a row of propane bottles.

The fire was started at a Walmart in Phoenix, Arizona, on Wednesday evening.

Surveillance footage shows two men and a woman walking away from the fireworks seconds after the fire is started.

Other footage, possibly filmed by one of the arsonists, shows the blaze quickly engulfing the top row of fireworks, accompanied by the caption "F—k Walmart".

Firefighters managed to extinguish the blaze before the flames reached a row of charcoal, lighter fluid, and propane bottles, Fox 10 Phoenix reports.

"Somebody could have been killed inside that store with that fire growing as fast as it did and as bad as it could have gotten," Phoenix Fire Captain Larry Subervi said.

Mr Subervi says the suspects could face up to a class two felony, which is just below a murder charge.

A number of Walmart staff were treated for respiratory issues. The store has been closed indefinitely, due to extensive water and smoke damage.