One man has been killed and another seriously injured in a crash involving three articulated lorries on the A9.
The collision took place at about 0520 GMT on the road north of Dunkeld, near Jubilee Bridge, in Perthshire.
Two HGVs collided head on before a third ploughed into the back of them. The road has been closed.
The scene was discovered by an ambulance transporting a patient to Perth. Emergency services found one man dead and another trapped in his cab.
He was eventually freed by fire crews using hydraulic cutting gear before being taken to Ninewells Hospital in Dundee with serious injuries.
Police said an unmarked silver tanker travelling north had collided with a green McKays of Montrose lorry going south.
The 57-year-old man driving the McKays lorry died at the scene and the tanker driver, 23, sustained serious leg injuries. The driver of the third lorry was uninjured.
Motorists have been warned to avoid the area.
One motorist, who passed the scene shortly after the crash took place, said: "We had to turn back and take a different route.
"We didn't get too close to the crash - but from what we could see it was a scene of devastation.
"It's terrible to think that someone has died this close to Christmas when they were just going about their business."
The crash took place on a single carriageway section of the A9.
The Scottish Ambulance Service said three ambulances and an RAF helicopter were sent to the scene, as well as the trauma team from Ninewells Hospital.
A spokesman for Tayside Fire and Rescue said: "One appliance from Dunkeld, one from Pitlochry, one from Perth and a heavy rescue unit from Perth were sent.
"The call came in at 05.29. They used cutting gear to release one of the trapped driver.
"Hydraulic cutting gear was also used."
Tayside Police have warned motorists that the road is likely to be closed for a long time.
A spokesman for the force said: "Accident investigators are on the scene. It will take quite some time to clear as it is three lorries involved."
The A9 has been closed to northbound traffic at Perth's Inveralmond roundabout, with a diversion in place for cars and lighter vehicles, returning to the A9 at Balinluig.
Southbound, cars and light vehicles are being diverted via the A924 at Pitlochry to Blairgowrie and then to the A93 to Perth. There are no diversions in place for heavy vehicles.
It is not yet known if the icy conditions played a role in the crash.
Temperatures in Perthshire plummeted overnight, with -15C recorded at Strathallan.