CHAMONIX, France (AP) _ Firefighters and police gingerly entered the Mont Blanc tunnel on Monday, searching through the wreckage of charred cars and trucks to try to identify the remains of dozens of victims.

At least 40 people died in the blaze that broke out Wednesday. Only five of them have been identified, and rescue workers say the death toll in the blaze still could rise.

Radio reports said small fires were still burning Monday, but temperatures in the tunnel had dropped sufficiently for rescue workers to go in. The workers had to be careful, however, because there were fears that parts of the severely damaged tunnel's ceiling could collapse.

French Prime Minister Lionel Jospin and his Italian counterpart Massimo D'Alema arrived Monday to pay tribute to the dead.

``When I ponder certain images that were shown to me, there are no words to describe my immense compassion for the victims and their families,'' Jospin told reporters.

Two bodies were taken from the seven-mile tunnel on Sunday but the evacuation process was proving slow.

Firefighters say it is still possible they will discover more bodies at the center of the tunnel, where massive chunks of concrete litter the road.

The fire broke out on a Belgian truck carrying flour and margarine through the tunnel. It raged for 50 hours until dozens of firefighters from France, Italy and Switzerland managed to control the blaze. All but a few of the victims died in their vehicles.

The tunnel near Chamonix, a French Alpine resort at the foot of Mont Blanc, connects Italy and France and serves as a major trucking route. It is expected to be closed for weeks.

French judicial authorities immediately opened an investigation, and say criminal charges may eventually be brought.

French and Italian officials will meet in Turin on Wednesday to discuss initial findings, Jospin said. The French premier also said studies would be carried out on 20 tunnels in France to assess security standards.

A recent report by the fire department of the Haute-Savoie region where the tunnel is located has raised questions about the feasibility of carrying out rescue operations inside the tunnel in case of a serious accident.

But French officials have rejected criticism that security measures were inadequate.

About 2,000 trucks pass through the tunnel on an average day. Local politicians are demanding that the road to be closed to truck traffic.