NOGALES, Ariz. -- The FBI is investigating an explosion at a power plant in southern Arizona caused by a makeshift bomb.
Nogales police say the explosion Wednesday morning at the UniSource Energy Services Valencia Plant ruptured a diesel storage tank and caused a small spill, but the fuel didn't ignite.
Authorities say there were no reported injuries and they're still looking for suspects and any witnesses to the explosion which occurred around 9:30 a.m.
The FBI and Bureau of Alcohol, Tobacco, Firearms and Explosives were called to the scene along with the Arizona authorities.
Nogales police spokesman Lt. Carlos Jimenez told The Arizona Republic that the plant is an electrical substation and has about 30,000 customers in the area.
Jimenez says the entire border town of Nogales depends on the plant for power.
Information from: The Arizona Republic