Sun May 3, 2009 10:16pm IST

HERAT, Afghanistan, May 3 (Reuters) - Italian troops fired on a passenger car in western Afghanistan on Sunday, killing a 12-year-old Afghan girl and wounding three members of her family, the family said.

A spokesman for the Italian contingent in Afghanistan said the girl was in a car that was driving at high speed and had ignored warning signs.

"Given that the car continued racing, despite the signals and warning shots, the soldiers opened fire aiming at the engine," said the spokesman by phone from Herat. "An investigation is under way. It is not clear exactly how the child died."

Reuters television footage showed a white Toyota car with its rear and side windows destroyed and its frame punctured with bullet holes. The girl, named Behnooshahr, lay dead on a gurney at a hospital in Herat, a city near the Iranian border.

"Suddenly I heard a loud bang, I couldn't work out what it was, but I saw that my daughter was dead and my family were badly hurt," said her father, Ahmadi, who did not give a last name and is from the neighbouring province of Farah.

He said the military convoy was driving behind him and he could not see or hear any signals to slow down or pull-over. After firing, the convoy continued to drive past his car and did not stop to help his family reach a hospital, he said.

Italian officials gave the girl's age as 13, but her family said she was 12. Italian Foreign Minister Franco Frattini was deeply saddened by the incident, a ministry statement said.

NATO forces in Afghanistan say they are working hard to reduce the number of civilian casualties, which have steadily increased. Western troops, fearful of suicide bomb attacks, have often been involved in shooting incidents on roads.

Troops are permitted to fire warning shots if cars do not give way and can fire directly at cars that still do not obey.

Barakatollah Mohammadi, a doctor who treated the family at a hospital in Herat, said he was shocked at the extent of the girl's wounds: "Her head was almost severed from her neck." (Additional reporting by Jalil Ahmad Rezaie in Herat and Antonella Cinelli in Rome; Writing by Golnar Motevalli; Editing by Peter Graff)