Eugenio Giani, head of the central Tuscany region that includes Florence and Pisa, told citizens to exercise "maximum care and attention", warning of "intense and persistent rain" during the day.

Florence authorities ordered the Uffizi Galleries, the world-famous art museum, to close early, and the Duomo said it was also shutting.

The fire service published images of cars partially submerged in the town of Sesto Fiorentino, north of Florence, with Giani telling residents to keep clear of ground floors and basements.

More than 500 firefighters were working across Tuscany, the interior minister said, with more than 300 interventions either carried out or planned.

Bernardo Gozzini from the Tuscan weather service Consorzio Lamma told the Corriere della Sera that 60 millimetres (2.4 inches ) of rain had fallen in the area around Sesto Fiorentino between 6:00 am and noon.

"In Florence, in the month of March, we usually have 70 millimetres of total precipitation," Gozzini said.

"In practice, it is as if a month's worth of rain had fallen in six hours."

- Floodgates opened -

Schools, parks and cemeteries in Florence and nearby Prato were already closed after an order on Thursday.

Giani said floodgates and expansion tanks had been opened to ease the pressure on the Arno, the river that runs through Florence and Pisa.

In Florence, the Arno was expected to surge to its highest point in the early evening, he said.

Alessio Mantellassi, mayor of Empoli, a town west of Florence, said in a live post on Facebook that the situation "is worse than in 2019", when Empoli flooded.

"It's one of the hardest moments in recent history," he said.

In Pisa, army soldiers placed sand bags behind the barrier lining a swollen river, while in Florence the Arno was lapping at the top of the river walls, in images published by Giani on Telegram.

Across Tuscany's border in Emilia Romagna, where devastating floods left 17 people dead two years ago, authorities also issued a red weather warning.

Some rivers in the region, which includes the historic city of Bologna, were already swollen by previous downpours.

Michele De Pascale, president of Emilia Romagna, said there had been "very violent" weather on Friday morning.

"We must pay great attention, it is a basin that has been hit several times in recent years by floods," he said in a statement.

Scientists have repeatedly warned that man-made climate change amplifies the risk of natural disasters such as floods.

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TUSCANY INTERNATIONAL DRILLING