A fire early Thursday in the eastern French city of Strasbourg has left five people dead and seven injured, the rescue services said.

The fire broke out overnight in a seven-storey apartment block and firemen had to evacuate many people as thick smoke enveloped their homes, a statement said.

The dead were three men in their 30s and 40s and two women - one 25, the other in her 70s, officials said.

"They died on the spot, overwhelmed by the smoke... and the heat of the fire in the stairwell," one local official said.

"The firemen told us that the walls were literally melting," he added.

The seven people hurt were in a relatively serious condition while those evacuated from the building were initially taken to a local gym for shelter, the rescue services said.