At least six people have been killed after heavy rainstorms and flooding in the Italian city of Livorno.

Four members of a family were killed when their basement apartment flooded. Italian newspaper Il Tirreno reports that two parents and their son died.

One girl was rescued by her grandfather, but he died when he returned to attempt for his other family members, the newspaper said.

Pictures from the city showed large areas underwater and extensive damage.

One resident, Piero Caturelli, said he had never seen such bad weather.

"It's incredible, incredible. It started around 10pm and continued until this morning. In my living memory, there's never been anything like this," he said.

Mayor Filippo Nogarin told the AFP news agency that the extent of the flooding was completely unexpected, as only an orange alert was issued.

The city in Tuscany was the worst hit, but weather warnings have been issued for much of the country.

Precautions are being taken in the capital, Rome, where the highest level of alert is in place.