“This is the first such accident in the history of the mountain,” said Gino Comelli, who was helping to coordinate rescue efforts.
The peak was too unstable for rescuers to try to approach on foot, Comelli said, adding that recent hot weather had been a factor in the collapse.
Pope Francis said he was praying for the victims and their families.
“The tragedies that we are experiencing with climate change should force us urgently to pursue new ways that respect people and nature,” he said on Twitter.
Rising average temperatures have caused the Marmolada glacier, like many others around the world, to shrink steadily over recent decades.
“The Marmolada glacier collapse is a natural disaster linked directly to climate change,” said Poul Christoffersen, a professor of Glaciology at the University of Cambridge.
“High elevation glaciers such as the Marmolada are often steep and relying on cold temperatures below zero degrees Celsius to keep them stable,” he added.
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