PARIS, July 18 (Xinhua) -- The "criminal" intent is currently the leading theory in the investigation of a fire in Nice, France, which resulted in seven deaths, said Nice prosecutor Damien Martinelli on Thursdaypokerroomnearme.

"In light of the initial findings, I have opened an investigation for acts of arson causing death," he told the presspokerroomnearme. The magistrate reported that "three children and a teenager" were among the victims.

The seventh floor of a residential building in a low-income neighborhood of Nice caught fire Wednesday overnight. Rescuers were alerted and 25 engines and 72 firefighters were deployed, according to local media reports.

The fire also left three people injured, one of whom was hospitalized in critical condition, reported the France Bleu radio.

"The swift action of the firefighters likely prevented many additional casualties," said French Interior Minister Gerald Darmanin.

According to France Bleu, the rescuers rescued three residents from the flames and ensured the safety of 33 others.■