Seventeen people, including a child left in a critical condition, were injured when soldiers fired live bullets instead of blanks during an open day display in Carcassone, France, regional officials said.
Fifteen civilians and two soldiers were injured in the incident, of which the details remained unclear, involving a demonstration by members of a marines parachute regiment of hostage liberation exercises, the regional authority said.
Four of the 17 were seriously injured, with two described as critical following "incomprehensible" scenes at the barracks near Carcassone, in the country's south-west.
According to local authorities, five children were among the injured.
Five helicopters, 11 firefighters' first-aid vehicles and two ambulances rushed to the scene to help the injured.
One soldier had been detained, although no explanation was immediately forthcoming for why the wrong ammunition was loaded into weapons.
"All hypotheses are being considered," said a national police spokesman tonight, adding that the weapons had been "seized and placed under lock and key".
Hospitals in the southern cities and towns of Toulouse, Narbonne, Montpellier and Perpignan, as well as Carcassone, were treating the wounded.
Colonel Benoit Royal, head of the army's information unit, said a number among the injured were from military families.
French President Nicolas Sarkozy urgently awaited the results of a top-level military probe into the incident, according to a presidential statement.
Sarkozy said he "shares with the families the pain caused by this drama. My first thoughts are with the victims. Everything will be put in place to care for them".
Lemaire added that investigators believed the deadly ammunition was loaded by mistake.
"The question being asked is 'Did the soldier engage in a criminal act or not?'," Lemaire said. "For now, no one can answer that, but the theory being worked on is one of error."
France's Defence Minister Herve Morin went "immediately" to Carcassone tonight, he said in a statement.
AFP