SIX homes had to be evacuated in a small hamlet after two tonnes of the highly explosive ammonium nitrate were found during a barn fire.

Residents of Gummow's Shop were warned to keep their doors and windows closed following the fire in a barn on a farm involving hazardous materials.

But after the discovery of the highly volatile fertiliser which caused the massive explosion in Beirut last year killing more than 200 people and injuring more than 6,000, it was decided to evacuate.

The incident commander told ITV news that because of the volatility of the material, the high winds and smoke plume it was decided to evacuate the six homes nearby.

It has been described as a "multi-agency incident" in the area of Gummow's Shop, a hamlet in the St Newlyn East area, not far from Newquay.

In a message described as 'urgent', Cornwall Fire and Rescue Service wrote on Twitter: "Urgent - Due to a multi-agency incident in mid Cornwall, we are advising all residents in the area of Gummow's Shop to keep doors and windows closed."

It was initially not clear at first whether it was connected to a large barn fire currently ongoing at Tredinnick Farm. 

Now the fire service has given an update to confirm that the warning is indeed linked the blaze, which has fire engines from 11 stations currently at the scene, along with Devon and Cornwall Police, South Western Ambulance Service, Cornwall Council, Public Health England, Environment Agency and the Met Office.

It is said to involve hazardous materials, although the exact nature of these has not yet been revealed. 

A fire service spokesperson said a 999 call was first made just before 11.45am, reporting a fire in a barn.

Two crews from Newquay and one from Truro were initially sent, along with a station manager.

On arrival, however, the first firefighters at the scene sent a message calling for first four pumps, then six, and then eight, as well as for water carriers and an aerial appliance to tackle the flames from above.

The Operational Support Unit, Environmental Support Unit and Incident Command Unit were also called in.

A tactical commander has now taken command of the incident and is working with counterparts from the police and ambulance service to develop a plan to resolve the incident.

Resources are currently on scene are from Newquay, Truro, Perranporth, St Columb, St Dennis, Wadebridge, St Austell, Tolvaddon, Liskeard, Penzance and Launceston.

The spokesperson said: "This is a multi-agency incident involving Cornwall Fire and Rescue Service, Devon and Cornwall Police, South Western Ambulance Service, Cornwall Council, Public Health England, Environment Agency and Met Office.

"The advice to members of the public at present is to keep doors and windows closed if you live in the area of Gummow's Shop, Summercourt."

Traffic reports are showing the A3076 is blocked in both directions due to the building fire between A30 Mitchell turn off and the A3058.