Falmouth Docks has been evacuated and police have declared a major incident after a crane collapsed.
Police, fire and ambulance services are currently on the scene.
Emergency services were called just before 9.10am on Wednesday and a 200m exclusion zone has been put in place.
It is believed the crane which had dominated the skyline for more than 50 years was in the process of being dismantled.
Sara Lucy, who lives near the docks, told The Independent she was woken by an "almighty long crashing noise which sounded like an explosion."
Devon and Cornwall Police said there were no reports of any injuries but Cliff Road was closed to the public.
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A spokesperson for the force said: "Police were called just before 9.10am to The Docks in Falmouth, following reports of an industrial accident.
"A crane has fallen over at the Docks and a 200m exclusion zone has been in place.
"Cliff Road is closed to the public and Cornwall Fire and Rescue are in attendance.
"Properties will be evacuated and Cornwall Fire and Rescue have declared a major incident.
"There is a full yard evacuation and police are assisting with traffic".
Navy Lookout tweeted: "Crane at A&P Falmouth just collapsed on RFA Tidespring in drydock. Enormous bang & sirens sounding. Hope no casualties.
"Fortunately RFA Tidespring undamaged - Crane collapsed on the dockside. Assume no injuries but yard evacuated."Reuse content