Police say as many as eight vehicles were involved in a pile up, just south of Ballaugh Bridge at lunchtime today.
At least one person has serious injuries and was airlifted to hospital.
It's understood motorbikes and cars were involved in the incident.
The stretch of the TT course from Douglas Road Corner, Kirk Michael to Ballaugh Bridge has been closed to traffic since just after midday, and will remain so until 6pm at the earliest.
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