Floods that killed at least 13 people in Italy's northern Emilia-Romagna region caused billions of euros' worth of damage and hit agriculture particularly hard, the regional governor said on Thursday.

Torrential rains this week devastated the eastern side of the region, known as Romagna, with up to 300 landslides, 23 overflowing rivers, some 400 roads damaged or destroyed, and 42 flooded municipalities.

"We are facing a new earthquake," Emilia-Romagna President Stefano Bonaccini told reporters, recalling the seismic events that struck the region in 2012, destroying thousands of homes.

Noting that since then "almost everything" had been rebuilt, Bonaccini said, "that experience showed us that it can be done, and we will rebuild everything (again), I am sure of that."

The death toll rose to 13 on Thursday when four more bodies were found. In the small town of Russi two people, aged 73 and 71, were found dead together in their home, local authorities said.

According to the Coldiretti agricultural association, more than 5,000 farms were left under water in the region, which includes a so-called "Fruit Valley", as well as corn and grain fields.

"We had already estimated almost 1 billion euros of damage (from those floods), so imagine how much the figure will rise" with the new disaster, Bonaccini said, adding it was too early to give precise figures.

The floods are the latest in a series of extreme weather events that have slammed Italy over the past year, as once exceptional disasters become a regular part of life.

The government has promised an extra 20 million euros ($22 million) in emergency aid, on top of the 10 million euros allocated in response to previous floods two weeks ago, which killed at least two people.

Luxury sportscar maker Ferrari RACE.MI, which is based in Emilia-Romagna, announced a 1-million-euro donation.

NO ELECTRICITY

At least 10,000 people were forced to leave their homes, and many of those who remained in flooded areas were left with no electricity. One of the dead was swept away from her home and washed up on a beach some 20 km away.

With the floods disrupting road and rail transport across the region, airport workers' unions agreed to postpone a strike that was planned for Friday following a request from the government.

In the town of Cesena, rain stopped and waters largely receded, allowing locals to regain access to their mud-wrecked homes, including couple Maurizio Cola and Raffaella Zanni who escaped early on Wednesday.

"We had to throw everything away, nothing was saved. Water arrived up to here. The bed expanded with the water," Cola told Reuters, while Zanni wiped away tears, mourning the loss of one of her most precious belongings: her wedding album.

"All the memories," Cola said.

"Finished", Zanni added.

Sunday's Formula One Grand Prix in Imola, which is close to many of the worst-hit areas, was called off to relieve pressure on emergency services, while a Bruce Springsteen concert in Ferrara later Thursday was set to go ahead as planned.

It was the second time this month that Emilia-Romagna has been battered by bad weather. Heavy rains followed months of drought which had dried out the land, reducing its capacity to absorb water, meteorologists said.

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