At least four students were injured after an experimental rocket exploded at the University of Idaho, school officials said early Friday.

The incident occurred in a school parking lot next to a campus steam plant, the University of Idaho said. Emergency personnel arrived at the scene and transported the individuals to Gritman Medical Center, the university confirmed in a statement on Twitter.

Parents of the victims were notified, the University of Idaho confirmed, adding that all victims were "alert" and "communicating" with school personnel. Their identities and injuries were not disclosed.

Grant Thurman, a member of the school's Northwest Organization of Rocket Engineers, told the Moscow-Pullman Daily News that the explosion resulted from the club testing rocket fuel it had created.

The University of Idaho said the incident was not a bomb threat. The FBI arrived on the scene, which Moscow police said is routine protocol.