French police on Sunday ended their practice of hiding plastic explosives in air passengers' luggage to train bomb-sniffing dogs after one such bag got lost, possibly ending up on a flight out of Paris' Charles de Gaulle (search) airport.

The luggage that police used Friday for the exercise has yet to turn up. Three flights that arrived in Los Angeles and New York were searched, but it was not found.

And no passenger has contacted French authorities to report the surprise discovery of a bag of nearly five ounces of explosives tucked into his or her suitcase.

Police say there was no chance the explosives could go off, since they were not connected to detonators. Still, Prime Minister Jean-Pierre Raffarin (search) was critical of the mistake.

"The fight against terrorism and insecurity is a priority for the government," a statement by his office said. "But (Raffarin) made clear his concern in the face of the way the training for explosives searches was conducted at Roissy Charles de Gaulle."

Raffarin said the procedure was "susceptible to making the relevant passenger run a risk in the eyes of foreign authorities when arriving in the destination country."

Police soon after announced they'd ordered a stop.

"The procedures that were used Friday night will no longer be allowed," said Pierre Bouquin, a spokesman for France's police force that conducted the training. "We're going to stop practicing this on the bags of travelers" in all of France, he said.

Airport police deliberately placed a bag containing up to five ounces of plastic explosives in luggage early Friday evening, Bouquin said. The luggage was lost on a conveyor belt carrying bags through a restricted area from check-in to planes.

The explosives could have made it onto one of up to 90 flights leaving Charles de Gaulle airport. Police didn't know the bag's destination and quickly alerted the relevant airlines.

Two police officers faced disciplinary action because of the incident, Bouquin said.