A woman in her twenties has died on Llantwit Major Beach after part of a cliff reportedly collapsed and she was hit by falling rocks.
South Wales Police are refusing to comment on exactly what happened at the beach, which is in the Vale of Glamorgan, but they and the Welsh Ambulance Service confirmed that a woman had died.
The identity of the woman has not yet been released.
A police spokesman said: "South Wales Police officers are in attendance at an incident at Llantwit Major beach which was reported shortly before 5.30pm this evening.
"A woman in her 20s has been declared deceased."
Police, ambulance crews, a rapid response vehicle, Welsh air ambulance, hazardous area response team and coastguard were all called out to the major incident, which took place just before 17:30BST.
On social media a number of posts reported that there had been a partial collapse of the cliffs which led to the tragedy.
There are a number of warning signs at entrances to the beach warning users of the perils of falling rocks. On TripAdvisor, one review says of the beach: "It is of course a great area for fossil hunting; but the cliffs faces, as elsewhere, are dangerous."
Police have appealed for anyone who was on the beach when the tragedy occurred to contact them on 101 or via Crimestoppers on 0800 555111 and quote reference 1500217238.
In 2012 a woman died at Burton Bradstock, near Bridport when a cliff partially collapsed. Charlotte Blackman, 22, from Derbyshire was on the beach with her boyfriend and father when a huge cliff collapse engulfed her.
Also in 2012 biologist Nick Paige, 24, died instantly when he was crushed by a rock fall in Madagascar. Paige, from Suffolk, was working on a project. His French colleague Stephanie Bollard also died in the tragedy.