A slab of ice broke off Thursday in the French Alps, sparking an avalanche that swept nine Europeans to their deaths as they tried to climb Mont Blanc, authorities said.

The Associated Press reported that eleven other climbers were hospitalized and at least four are still unaccounted for.

The avalanche, which came after unusually wet weather, sent climbers hurtling down steep slopes at the height of the summer climbing season. Police said one of the climbers may have kicked the ice sheet loose.

The dead were from Britain, Germany, Spain and Switzerland, the gendarme service in the French mountain town of Chamonix told AP.

A group of climbers from Switzerland, Germany, Spain, France, Denmark and Serbia were caught in the early morning avalanche some 4,000 meters high on the north face of Mont Maudit, part of the Mont Blanc range.