San Francisco  - Three crew members were killed when an air tanker crashed shortly after taking off to fight a fire in the Sierra Nevada mountains, officials said Tuesday.

The twin-engined P2V air tanker was owned by Neptune Aviation of Missoula, Montana and had already made one run before returning to the airport in Reno, Nevada to load up on fire retardant.

Witnesses reported that it burst into flames shortly after take- off Monday evening to fight a second blaze, crashing about one kilometer from the airport.

However officials said that the call for air support had been cancelled shortly before take off because ground crews has the blaze under control. (dpa)