Fifteen pilot whales in trouble in Kyle of Durness
Two whales have come ashore and up to 15 others were in difficulty in shallow water at Kyle of Durness, on the north Highland coast.
The Maritime and Coastguard Agency (MCA) said the whales were believed to be from a pod of as many as 60.
The long-finned pilot whales may have been hunting prey or had sought a place to rest.
A Royal Navy bomb disposal team training in the area has offered its help in any rescue effort.
British Divers Marine Life Rescue (BDMLR) and Scottish SPCA inspectors headed for the scene.
Highland Council countryside ranger Donald Mitchell and nine coastguard volunteers have been monitoring the situation.
Mr Mitchell said that at low tide only a narrow channel of sea remained.
Kyle of Durness opens out into Balnakeil Bay.
Charlie Phillips, a Whale and Dolphin Conservation Society (WDCS) field officer, said the area was remote and it would take rescuers sometime to reach the scene.
Mr Phillips told the BBC News Scotland website: "It is going to be tricky.
"It is a remote and difficult place to get to."
Mr Phillips added: "The whales may have come in from the Pentland Firth, following prey or trying to find somewhere to rest."Marine strandings
He said a young female pilot whale was found at Scourie, in Sutherland, a few weeks ago.
The Scottish Agricultural College (SAC) said it understood that two whales were stranded on the shore.
SAC vet Dr Andrew Brownlow, who leads the Scottish Marine Animal Strandings Scheme, was driving to the scene.
The college said: "The latest report is that two of the whales have become stranded on the shore, 15 are currently in shallow water and at significant risk of becoming stranded and at least another 20 whales may be heading towards the shallows.
"Should any of the whales fail to make it back out to sea and do not survive, Dr Brownlow will lead post mortem examinations with the aim of identifying what has caused them to come ashore.
"This enables the Strandings Scheme to monitor trends in causes of marine strandings which in turn allows identification of any new or developing hazards to marine mammals in Scottish waters."
In May, two pilot whales were found dead in a Hebridean loch after experts feared more than 60 of the animals had been at risk of becoming beached.
The pod had got into difficulty in Loch Carnan in South Uist.