The shattered bridge spanned a stream into which much of the rubble fell/EPA
A bridge collapse in Italy's Genoa city may have killed "dozens" of people.
A section of a viaduct on the A10 motorway collapsed on Tuesday with cars and trucks trapped in the rubble, firefighters said.
Television images showed the Ponte Morandi viaduct in the mist with a huge chunk missing, with Italian media reporting that 200 metres had fallen away, according to Al Jazeera report.
A witness told Sky Italia television he saw "eight or nine" vehicles on the bridge when it collapsed in what he said was an "apocalyptic scene".
The Italian news agency Adnkronos reported "dozens of dead", citing the ambulance service.
An ambulance official told Reuters news agency it could only confirm two injured people so far, "but we suppose there are unfortunately a lot of dead".
Rescue workers and dogs began searching the rubble 50 metres below the bridge. Two people have been found alive so far and flown to hospital by helicopter.
A firefighter told RAI state television that some 20 vehicles were involved in the collapse.
The fire service said the viaduct, located over a river in an industrial area in the west of the city, collapsed at around 10:00 GMT.
It wasn't yet clear what caused the bridge - which was built in the 1960s - to collapse. Restructuring work on it was carried out in 2016.
As details emerged, the country's transport minister Danilo Toninelli said the incident seemed to be "an immense tragedy", adding he was travelling to the scene of the collapse.
"I am following with the greatest apprehension what has happened in Genoa," Toninelli wrote on Twitter.