Screenshot via Twitter A fire engulfed a bar in northern France, killing at least 13 people and injuring six others, CNN and the Associated Press reported Friday night.

It happened overnight Friday into Saturday morning local time, in the city of Rouen in Normandy.

Witnesses who spoke to CNN said emergency vehicles set up a perimeter around the Le Cuba Libre bar on Avenue Jacques Cartier.

The bar had apparently been rented out for a birthday party, Le Monde reported.

The newspaper, citing French interior minister Bernard Cazeneuve, said more than 50 firefighters were called to the scene.

Cazeneuve said a judicial inquiry was opened as investigators look at what caused the fire. Local deputy prosecutor, Laurent Labadie, told Paris-Normandie the fire may have been accidental, and several reports suggest that candles on a birthday cake may have started the blaze after setting fire to flammable sound insulation in the ceiling of the bar.

Terrorism has been ruled out by the authorities, according to reports from The Guardian and the BBC.

A map showing the city of Rouen in northern France. Screenshot via Google Maps

Terrorist attacks have plagued France and Germany over the past few weeks. Last month 84 people died in Nice after a man rammed a refrigerated truck into crowds enjoying Bastille Day festivities, and just last week an 86-year-old priest was killed and three others were injured in a knife attack on a Catholic church in Normandy.

Both of those attacks were claimed by ISIS, the terrorist group also known as the Islamic State, ISIL, or Daesh.

Barbara Tasch contributed to this report.