Emergency services have been using dinghies to rescue people from their homes, and footage from the scene shows cars floating in the streets.

The governor of the Veneto region described the weather overnight as being like a "water bomb".

Meanwhile the south of Italy is experiencing an unseasonal heat wave, with temperatures reaching up to 35C in Sicily.

Speaking to the Corriere del Veneto newspaper, Professor Marco Marani, an expert on the impact of climate change at the University of Padua, said: "Extreme events are becoming more frequent and will increase with the increase of global warming."

In the early hours of Friday, the banks of the Muson dei Sassi river in the Padua area gave way due to the heavy rain, resulting in severe flooding.

In Borgo Mantovano, Lombardy, a freight train was overturned by gusts of between 150 and 200km/h (93-120 mph) .

Local mayor Alberto Borsari wrote on social media that "many streets and basements were flooded" and the situation was "really tough".

"Luckily no-one was hurt," he added.

Milan experienced up to 130mm (5in) of localised rain in a single day, resulting in flash floods. Local observers said that such rain intensity had not been recorded in May for more than 170 years.

In Veneto, a state of red alert has been declared until 14:00 local time (12:00 GMT) by the Civil Protection authorities, especially between Vicenza and Verona where the water basins are overflowing after 70mm of rain in 30 minutes.

One person is missing in the Como area after the collapse of a small bridge.

In the south, Sardinia is experiencing very dry conditions, and is already dealing with another bad season for local wheat farmers, who are expecting half the usual harvest due to the lack of water, according to local newspaper L'Unione Sarda.

Water restrictions are also predicted in the area later in the summer.

Prof Marani said "there's strong scientific evidence" that extreme weather events were becoming more frequent, adding that the calculations for water defences "must be revised to understand the real risk we are facing".

"Climate change must be managed," he added.

In April, the new State of the Climate report by EU climate agency Copernicus and the World Meteorological Organisation highlighted the need for flood defences and the urgency of climate action.

Climate scientists calculated that in 2023 one-third of rivers across Europe breached the "high" flood threshold, while 16% swept past the "severe" mark.