A US Army Apache helicopter accidentally dropped an inactive missile over central Texas, forcing dozens of homes to be evacuated, officials said Wednesday.

No one was injured in the incident in which residents in Killeen told police they saw an object falling from an AH-64 attack helicopter into a field late Tuesday, according to a statement from the army's Fort Hood base near Killeen.

"Killeen Police Department responded and located the object which was impaled into the surface of the ground. Officials immediately cordoned off the area," the statement said.

No one was injured in the accident but local media said about 100 homes were evacuated.

An explosive disposal team found an inert M36 missile, a dummy version of a Hellfire missile used for training, officials said.

"The M36 is an inert training device without a warhead or propulsion system and is designed to enable crews to simulate Hellfire missile engagements in the cockpit without launching from the aircraft," the Fort Hood statement said.

The dummy missile, just like a real Hellfire weapon, weighs about 100 pounds (45 kilograms) and is 64 inches (163 centimeters) long.

The cause of the incident was under investigation, said Colonel Howard Arey, III Corps aviation officer.