June 30 (Bloomberg) -- A mock hostage rescue at a military base in the south of France left 17 people injured after a soldier fired real bullets instead of blanks.

``There were unacceptable instances of negligence,'' President Nicolas Sarkozy said as he arrived in the southern city of Carcassonne to visit the wounded. ``They must be sanctioned. The reaction must be rapid and severe.''

The mix-up between blanks and live bullets during an ``open day'' for the public yesterday was the result of human error ``and not in any way premeditated,'' Brice Robin, the state prosecutor in the regional capital of Montpellier, said in an interview with LCI television.

Benoit Royal, a French army spokesman, told LCI that only one soldier fired live ammunition in the operation yesterday and an investigation is under way to discover why. He said it was ``99.9 percent likely that it wasn't voluntary.''

The soldier, a sergeant with the Third Marine Parachute Regiment that was simulating hostage rescue at the base near Carcassonne, is being questioned, Royal said. The spokesman said blanks and live ammunition have different colors and it's against regulations to store them together.

``What happened is incomprehensible,'' said Defense Minister Herve Morin, who accompanied Sarkozy. ``Procedures put in place should make this impossible.''

The soldiers were using France's standard issue Famas assault rifle.

Of the injured, two are military and 15 are civilian, one of them a 3-year-old. None of their lives are in danger, LCI said.

To contact the reporter for this story: Gregory Viscusi in Paris at gviscusi@bloomberg.net.

Last Updated: June 30, 2008 11:04 EDT