Four bodies were pulled from the wreckage of the UH-60 Blackhawk Army chopper, which crashed near Treviso, and another six people on board were injured and sent to area hospitals, said Luca Cari, a spokesman for the national fire department.
The ANSA and Apcom news agencies said five people were believed to have been killed; Cari said it was possible a fifth may have died at the hospital but that fire officials at the scene had only confirmed four dead.
A spokesman at the U.S. Air Force base in Aviano, near Venice, Senior Airman Justin Weaver, said he had no confirmation on the number of deaths but that the chopper involved had taken off from Aviano.
Weaver said the Blackhawk crashed in the countryside outside of Treviso, in the uninhabited area of St. Lucia di Piave. The location is about 40 kilometers (25 miles) southwest of Aviano, which in turn is about 115 kilometers (70 miles) northeast of Venice.
Television footage showed the charred remains of the chopper, which broke into at least two large pieces, smoldering in a swampy field.
The UH-60 Blackhawk is the Army's general utility helicopter used for transporting troops and equipment, air assault, medical evacuations and to support special operations as well as other missions.
An entire 11-person, fully equipped infantry squad can be lifted in a single Blackhawk, according to the Army web site, which says the helicopter has a crew of four.