US authorities say a hot air balloon carrying 13 people crashed and caught fire today in the desert outside Phoenix, igniting a small brush fire but causing no injuries.

Phoenix fire captain Jake Van Hook says it started "only a small amount of fire", which crews quickly extinguished.

A witness' video shows flames and a large plume of black smoke in an area of dry brush as several people on a dirt path look on.

The crash happened just before 8.30am local time north of the Phoenix metro area, according to Maricopa County Sheriff's officials.


Preliminary reports from the National Transportation Safety Board say it appears a tree branch punctured the balloon's colorful outer covering, known as the "envelope".

"That branch caught fire," NTSB spokesman Chris O'Neil said.

O'Neil said all 13 people safely evacuated the balloon's basket, which then caught fire.

The group attempted to put out the blaze with fire extinguishers, but it consumed the basket.

The NTSB and the Federal Aviation Administration are both investigating.

It's not yet clear if the pilot was trying to land when the puncture occurred.

"The sequence [of events] and the mechanics will become clearer as we go on," O'Neil said. "It's fortunate that no one was hurt."

No injuries were reported and no other information was immediately available, FAA spokesman Ian Gregor said.


The hot air balloon is registered to Hot Air Expeditions in Phoenix. A phone message left with a Hot Air Expeditions employee was not immediately returned.

- AP