By Matt Murphy
Watch: Video captures moment glacier collapses in Italian alps
At least five people have been killed after being caught in an avalanche sparked by the collapse of a glacier in the northern Italian Alps.
Emergency officials said eight others were injured in the collapse, with two people suffering serious injuries.
Five helicopters and dozens of emergency workers have been sent to the scene to assist with rescue efforts.
Video of the incident showed an ice mass collapsing down the slopes of Marmolada, the area's highest mountain.
"Unfortunately, five people were found lifeless," emergency services spokeswoman Michela Canova told the AFP news agency, adding that the injured figure "remains a provisional count."
"An avalanche of snow, ice and rock which in its path hit the access road when there were several roped parties, some of which were swept away," Ms Canova explained. "The definitive number of mountaineers involved is not yet known," she added.
The injured hikers, including one person left in critical condition, were taken to several hospitals around the area, rescue officials said.
In a tweet, the local emergency service said it believes that 15 people hikers were in the group at the of the collapse.
It isn't immediately clear what caused the section of the glacier, called a serac, to collapse.
But Walter Milan, a rescue service spokesperson, told state TV that the area has been experiencing unusually high temperatures in recent days.
"The heat is unusual,'' Mr Milan said, noting that temperatures have reached 10C at the glacier's peak in recent days.
"That's extreme heat," he said. "Clearly it's something abnormal."
Reinhold Messner, an Italian mountaineer, told La Republica newspaper that the glacier has been receding for several years due to the impact of global warming.
"There is hardly any ice left," Mr Messner said. He noted that glaciers occasionally collapse "due to gravity," but said the reason for the glacier's retreat "is the global heat, which causes glaciers to melt".