The A82 road has been closed in both directions between Arden and Balloch following a multi-vehicle crash on Wednesday afternoon.
The collision took place near Loch Lomond at around 2.30pm and Traffic Scotland confirmed the closure on social media soon after.
Emergency services are in attendance and drivers have been warned that delays are likely in the area with traffic heavier than usual through Helensburgh and Cardross.
Police are also in attendance.
A spokesperson for the force said: “Around 2.35pm, police received a report of a multi-vehicle crash on the A82 near Balloch.
“The road is closed between Stoneymollan Roundabout and Arden Roundabout and emergency services are on scene.”
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