Rivers broke their banks and heavy rain and winds smashed cars, flooded homes and brought down bridges on the island yesterday. The previous toll stood at nine.
"I believe there are 14 victims... The situation is dramatic," Cappellacci told news channel SkyTG24.
The port city of Olbia, where most of the victims were concentrated, was completely flooded and hundreds of people were forced to spend the night in temporary shelters and thousands have damaged homes.
Among the dead was an entire family of four Brazilian immigrants who drowned in their basement flat in the town of Arzachena in the northern part of the island.
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Emergency workers were still rescuing people in a mountainous part of the island near Nuoro who climbed onto the roofs of their homes or up trees to escape the rising waters.
In Olbia, hundreds of residents took to Facebook to offer their homes as shelter for the night to those forced out of their houses on a special group entitled: "Let us open our homes to our fellow citizens".