Marine animal experts are trying to prevent a mass stranding by up to 100 pilot whales in South Uist in the Western Isles.

The whales were spotted in Loch Carnan on Thursday afternoon and about 20 were said to have had cuts to their heads.

It is thought the injuries may have been caused by attempts to strand themselves on the rocky foreshore of the sea loch.

Rescuers said inflatable pontoons for refloating whales were on the way.

The pod has been moving back and forth from the shore and rescuers said the animals were "very vocal", which may be a sign of distress.

Members of the British Divers Marine Life Rescue (BDMLR) fear the whales could die in a massive beaching - which could be Scotland's largest stranding.

BDMLR Scottish organiser Alasdair Jack said: "Rather than try to stop them coming ashore, we would let them come ashore and then try to deal with situation when it arose.

"We have got several sets of pontoons with us, which is our whale refloatation equipment, and we have got more on the way.

"We have currently got 12 sets congregating on the Uists, which is basically every set in the UK."

Scottish SPCA senior inspector Calum Watt said the whales' strong social bonds meant healthy animals within a pod would follow sick and injured ones on to shore.

He added: "At this stage we remain hopeful they will not strand themselves but our concern is the injured whales will come onshore and be followed by the rest of the pod.

"Attempting to refloat so many whales would be a huge task and if they do become stranded we'll need to decide upon the best course of action.

"The largest number of whales we've tried to refloat before was seven, which was in 1993. Unfortunately all seven returned to the shore and died."

Wildlife tour operator Steve Duffield, who has photographed the pod, said it was unusual to see pilot whales so close to shore.

He said: "It is a deep water species and occurs in the Minch and Sea of Hebrides, but is very rarely seen in coastal lochs.

"To see the whales so close to the coast is exceptional."