A blaze at a storage shed in Invergordon that led to an oil rig and three schools being evacuated continued to burn into Monday evening.

Firefighters were called to the blaze at the Skretting fish food storeroom in the East Docks area of the Easter Ross town at 4.07am.

No one was injured but police set up a 200 metre exclusion zone around the area.

Highlands and Islands Fire and Rescue Service Assistant Chief Fire Officer, Dave Gill, said firefighters would remain at the scene for “some time”.

He said: "The operation to reach the seat of the fire may take some time yet due to its deep seated position within the storage shed.

"The number of bags of fish meal, which are very large, between us and the seat of the fire is making it a very painstaking process. We would like to reassure the public that we are working as hard as we can to resolve the matter as quickly as possible.

"We would like to thank the public for their forbearance and understanding whilst we deal with this incident. Our advice for people to remain indoors with windows and doors closed stands until further notice."

All workers onboard the Transocean-operated Sedco 714 oil rig, berthed in the Queen's dock at Cromarty Firth Port Authority, was evacuated as a precautionary measure.

Elsewhere, pupils and staff at Park Primary, South Lodge Primary and Invergordon Academy have been sent home.

Emergency services are advising residents to stay inside and keep windows and doors shut.

They insist that as the fire is non-toxic, the resulting smoke is safe, however it may cause mild irritation.

Local councillor Martin Rattray's home overlooks the base. He said: “I noticed first thing this morning smoke billowing out of the shed

Two fire engines were at the scene of the fire.

Skretting claims to be the UK and Ireland's largest aquaculture feeds producer. They employ around 60 workers at the Invergordon facility.

Environment and food watchdogs SEPA and DEFRA have been informed of the incident.