A trailer became “engulfed in flames” on the main road between Dundee and Aberdeen, sparking traffic chaos.
Fire crews were called to the A90, close to the turn-off for Glamis, after a trailer being towed by a car was reported to be ablaze at around 12.15pm.
The smoke could be seen “for miles”, according to one motorist who was stuck in the tailbacks.
A Scottish Fire and Rescue spokeswoman said: “We received the call at 12.16pm and one appliance from Forfar is on its way.”
A motorist said: “The fire was massive, you could see the smoke for miles.
“I was stuck behind lots of cars and when I eventually got through I could see the trailer on the hard shoulder. It was properly on fire, engulfed in flames.”
There are no reports of injuries at this time.