The victims, ranging in age from 18 to 25, were reportedly celebrating at a birthday party.

No identities have been disclosed and authorities have said they expect the death toll to rise, the "Paris-Normandie" newspaper reported.

Six people were reported to have been injured, with one said to be still in a critical condition.

Toxic fumes

Police said the fire broke out a birthday cake adorned with candles and sparklers fell on the floor, setting alight the carpet.

Many of the victims were overcome by toxic fumes when the polystyrene ceiling also caught fire, according to officials.

According to local police, fears the fire may have been an act of terrorism appear to be unfounded. They denied earlier reports that the blaze had been triggered by an explosion.

Investigators are looking into whether the business had met all building codes, according to Rouen mayor Yvon Robert.

France is under heightened security after several terrorist attacks in recent weeks, including the murder of a priest in a small town near Rouen.

Multiple injuries

The fire reportedly started at 0:50 a.m. local time on Saturday at Le Cuba Libre bar on the west bank of the River Seine.

Some 50 firefighters took 30 minutes to get the fire under control.

A support unit for families is being set up at the University Hospital of Rouen. Eleven witnesses have been taken to the Rouen central police station to be interviewed.

jbh/cmk (dpa, AFP)