A section of a giant motorway bridge collapsed Tuesday in Genoa, injuring several people in what Italy's transport minister said was an "immense tragedy."
Some Italian media, citing sources within the interior ministry, said that at least 11 people had died, though it was not immediately possible to confirm this figure.
Rescuers scouring through the wreckage after part of a viaduct of the A10 freeway collapsed said there were "tens of victims", while images from the scene showed an entire carriageway plunged on to railway lines below.
Cars and trucks were trapped in the rubble and nearby buildings damaged.
Italian media reported that 200 metres (650 feet) of the "Morandi" bridge had fallen away.
The Italian fire service said that the viaduct, located in an industrial area in the west of the city, collapsed at around noon (1000 GMT).
"I'm following with the utmost apprehension what is happening in Genoa and what looks like it could be an immense tragedy," transport and infrastructure minister Danilo Toninelli said on Twitter.
Italy's far-right interior minister Matteo Salvini said he was following events in Genoa "up to the minute" and thanked the emergency services for their swift response.
A fire service spokesperson told AFP that the bridge had mostly fallen on rail tracks 100 metres (yards) below and that "cars and trucks" had fallen with the rubble.
"Firefighters are working together and teams of rescuers and police sniffer dogs have been mobilised," emergency services said on Twitter.
Genoa is located between the sea and the mountains of northwestern Italy.
Its rugged terrain means that motorways that run through the city and the surrounding area are characterised by long viaducts and tunnels.