Rescuers are using bulldozers to try to push 55 pilot whales back into the water after they beached near the South African city of Cape Town.
South African rescue teams have managed to return to the water 20 pilot whales which beached near Cape Town but others have had to be put down.
High winds and waves are hampering the operation to save the adults and calves which came ashore in the early hours of the morning.
Bulldozers were used to try to push the 55 adults and calves back into the water as high winds and waves hampered the rescue operation.
But the whales are swimming back to the beach as soon as they are returned to the water, rescuers say.
The whales, about 3m (10ft) long, are common to the waters off South Africa.
The whales, about 3m (10ft) long, are common to the waters off South Africa.
Six bulldozers are being used in the rescue operation, and rescuers and volunteers are trying to keep the stranded mammals wet, National Sea Rescue Institute spokesman Craig Lambinon told reporters.
It is unclear how the mammals became stranded and some which were returned to the water swam back to the beach.
"As soon as we put them back into the sea, they swim back to the beach again," he explained. Rough seas were also pushing the whales back ashore.
Craig Lambinon, a spokesman for the National Sea Rescue Institute, told Reuters news agency that he could not say how many whales would have to be killed.
At least one whale has died.
Those who could not be saved were being shot humanely in the head.
Mr Lambinon said it was still unclear why the whales had come ashore. It was the first mass beaching of whales he had seen on the popular beach at Kommitjie, near Cape Point.
It was the first mass beaching of whales Mr Lambinon had seen on the popular beach at Kommitjie, near Cape Point.
Volunteer helpers and onlookers have flocked to the area, blocking the main approach road, reports say.
"As soon as we put them back into the sea, they swim back to the beach again," he said earlier.
Rough seas also pushed some whales back ashore.
Volunteer helpers and onlookers flocked to the area, blocking the main approach road, reports say.
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