At least two people have died and more than 60 were injured after a tanker drove into the back of another lorry on a motorway in Italy, generating two massive fireballs.
Video released by police shows the tanker driving along a motorway near Bologna.
Traffic slows but the tanker does not, and it barrels into a lorry in front of it, swinging its cab to the left in a last-second attempt to avoid collision.
A second later, flames shoot across the tarmac, engulfing vehicles and sending black, acrid smoke billowing into the sky.
The tanker was probably carrying liquified petroleum gas, the emergency coordinator for the local fire service, Giovanni Carella, said.
The carriageway was cleared after the initial collision – but police footage shows the tanker continuing to burn and smoke. The tanker then exploded in an enormous fireball, with the flames blasting across all six lanes of the road.
The crash, near Bologna airport, caused part of an elevated section of the motorway to collapse, with several vehicles in a car dealership below bursting into flames.
“The shockwave from the blast was extremely violent,” Mr Carella said.
“Many of the injured received cuts from flying glass, which had shattered.”
Marco Rosadini, who was at a nearby restaurant for work, said he thought it was a “terrorist attack”.
Mr Rosadini, whose car was trapped under the flyover, told La Repubblica: “After the explosion the roof of the restaurant started to collapse.
“I looked outside and I felt like I was looking at a wall of fire.”
More than a dozen people were seriously injured, local media said, including police officers and carabinieri (military police).
Some are said to be suffering serious burns.
Firefighters sent multiple teams to the scene, including an urban search and rescue squad.
The road collapsed because of the heat of the fire, police said.
Officers closed a major motorway junction in Borgo Panigale, on the outskirts of Bologna.
The junction connects two important routes linking northern Italy with the Adriatic coast.