Comedian Janey Godley was near the spot in Glasgow where a bin lorry killed "several" people and she compared the scene to a "horror movie".
Several pedestrians are feared dead after the council vehicle careered out of control in Queen Street and ploughed into Christmas shoppers.
Godley, 53, was in nearby Buchanan Street when she heard the commotion of on-rushing emergency service vehicles.
"It was like something out of a horror movie," she told. "The traffic poles in Queen Street were bent like straws as they had been run over by vehicles. I heard there was a taxi involved as well as the bin lorry and when I reached the scene I couldn't see the bin lorry.
"I saw one person on the ground being given CPR in Queen Street and then another two. It was really awful and you could hear the screams above the sirens," she told The Mirror.
A teenager who saw the tragedy said it had left him bady shaken. Reece Miller, 16, spokes of relatives of dead victims grieving over their bodies in the street.
He told the Telegraph: "We went out and saw lots of bodies lying on the floor.
"At the scene there was a woman lying on the floor, covered by a blanket. Her family were leaning over her grieving."