Six Russian tourists have died and two others have been injured after their snowmobile flipped over on a ski slope in north-eastern Italy, reports say.
The incident took place on a black run on Friday night near Trentino.
Italian media reports suggested the four women and two men were killed when they were thrown into a deep ditch.
It said the accident occurred late on Friday on a run which was unlit and normally closed at night.
The accident took place in at 2,000m (6,500ft) above sea level on the slopes of Mount Cermis, in the Fiemme Valley.
Investigators think that as the group returned to their hotel in the dark, they took a wrong turning, heading down an unlit and difficult black piste, instead of the easier and illuminated slope that they should have taken.
Their snowmobile then appears to have crashed through protective netting, before plunging a further 100 metres.
Speaking on Russian state television, the consul-general in Milan, Alexei Parmonov, named the dead as Denis Kravchenko, Irina Kravchenko, Vyacheslav Sleptsov, Yulia Yudina, Lyudmila Yudina and Rafilya Pshenichnaya, AP reports.
Five of the group who died, along with one of those injured, came from the southern Russian city of Krasnodar and two of those who died worked in Italy in the tourism industry, Mr Parmonov said.
Both of the injured were taken by helicopter to hospital, where one is reported to be in a serious condition.
La Repubblica newspaper reports that the search operation was made more complex by the fact that the victims ended up in a rocky and densely forested area beyond the ski run.
The BBC's Mark Duff, in Milan, says that is one of the busiest weeks of the winter skiing season in the Alps.
Mount Cermis has an unenviable reputation as the site of a number of serious accidents, our correspondent adds.
In 1998, 19 people were killed when a low-flying US warplane cut the cable of a ski lift on the mountain.
In 1976, 42 people were killed when another cable car fell more than 200 metres in what remains the world's worst ever cable car accident.