"Twelve dead in Sicily, people that were having dinner and were swept up by the water," Interior Minister Matteo Salvini said in a statement to the press in the northern region of Veneto.
Nine of the people were members of two families dining together when the house was submerged by water from a nearby river that overflowed suddenly, the Fire Brigade said on Twitter.
The Fire Brigade said on Twitter that its divers had found the bodies. Among the victims were two children, 1 and 3 years old.
The Civil Protection Agency said it's still looking for a doctor who had been on his way to work at a hospital Saturday night and is now missing.
High winds and heavy rain have devastated parts of the country over the past week, causing the worst flooding in at least a decade in Venice, damages of more than 1 billion euros ($1.14 billion) in Veneto and landslides that have cut off villages, authorities said.
The situation in Sicily is "dramatic," Prime Minister Giuseppe Conte said Sunday.
Conte will call a cabinet meeting to announce a state of emergency in affected regions, he said at a press conference in Palermo, Sicily.
Italy's Civil Protection Agency continues to monitor the situation, issuing weather warnings via Twitter, while volunteers from the Italian Red Cross work to rescue people.
Several of last week's deaths were caused by falling trees as winds as strong as 190 kilometers per hour (118 mph) toppled acres of woodland, including the famous "Violin Forest" that provided wood for violin maker Antonio Stradivarius' instruments.
Two young people died south of Rome when a tree hit their car. Another was hit by a falling tree while walking in Naples.
Around 300,000 trees were flattened after winds swept through the Val d'Assa in the Asiago plateau, Roberto Ciambetti, president of the Veneto Regional Council, told CNN.
"Tens of thousands of tall trees were felled like toothpicks," he said.
Much of Venice was under water as strong winds on Monday drove the high tide to one of the highest levels ever recorded.
St. Mark's Square became a lake, and floodwater spilled across the ancient marble floors of St. Mark's Basilica.
"In a single day, the basilica aged 20 years, but perhaps this is an optimistic consideration," Carlo Alberto Tesserin, head of the board responsible for St. Mark's Basilica, said in a statement.
Floodwaters also covered several dozen square meters of the 1,000-year-old marble pavement in front of the alter of the Madonna Nicopeia, a 12th-century icon, and submerged the Baptistery and the Zen Chapel, Tesserin said.
More about: Italy