PARIS (Reuters) - Eight people who are not answering their phones are believed to be under the rubble of two buildings that collapsed early Sunday morning in the southern French city of Marseille, local officials said.

 The collapse of two buildings in Marseille, France, and fears that 8 are under the rubble

 Marseille prosecutor Dominique Lawrence said on Sunday evening that the cause of the explosion was not yet known.

 She added in a press conference that the collapse caused a fire that complicated rescue efforts and investigations, adding that efforts to control the fire had not succeeded so far.

 Five people were taken to hospital with serious injuries, but they did not pose a threat to their lives.

 French Interior Minister Gerald Darmanin, who visited the disaster site, said a third building had been damaged and residents had been evacuated from around 30 buildings in the area.

 Housing Minister Olivier Clain told Europe 1 radio that some 180 people had been evacuated from their homes.

 The public prosecutor said there were no known structural problems with the two collapsed buildings on Rue de Tivoli.

 President Emmanuel Macron wrote on Twitter, "Our hearts are with Marseille."