Receding waters in the Italian port city of Genoa Saturday revealed heaps of overturned cars, furniture and mud strewn across the streets after flash floods that killed six people.

Two young girls were among the victims of the city's worst floods in four decades, prompting angry residents to lash out at the authorities for keeping schools open on Friday while Prime Minister Silvio Berlusconi blamed lax local construction laws.

As the rains moved to other parts of Italy, Genoa's historical centre was closed to private vehicles, as council workers and emergency services engaged in a huge clean-up effort.

Piles of mangled scooters and vehicles swept away like Matchbox cars, uprooted trees and Genoans' ruined home interiors littered the streets.

Nestled between the Ligurian sea and the Apennine mountains, Genoa was gutted by flash floods that erupted when 356 millimetres of rain -- or a third of the average annual rainfall -- came down in six hours Friday.

The torrential rains inflicted the worst such disaster Genoa had experienced since similar flash floods killed 25 people 41 years ago.

Emergency workers Saturday were bent on removing the thick layer of mud and silt churned up by the raging waters of the swollen Fereggiano torrent and now caking the floors of ground level homes, shops and museums.

"Shame on you, shame, go home, resign," were some of the shouts that greeted the industrial city's centre-left mayor Marta Vincenzi when she toured some of the most affected areas Saturday.

Many residents were angry that the mayor's office failed to close down schools and ban traffic on Friday, arguing that lives could have been saved and some of the destruction avoided.

Five of the victims, including the two schoolgirls, died when the lobby of an apartment block in which they had sought shelter flooded.

Berlusconi deplored the presence of buildings "erected where they shouldn't be."

Several experts pointed to lax regional legislation which reportedly brought the minimum security distance from a river for any new building from 10 to three metres.

It was still raining on the city of 600,000 Saturday, as well as on La Spezia, also in Liguria, and in the northern Tuscan area of Lunigiana, where flooding has killed 10 other people in recent days.

Rescue workers were proofing roads near La Spezia for the risk of landslides. Two hamlets were completely evacuated while a shelter with a capacity of 1,000 people was also opened on the Tuscan coast.

Given the continued rainfall, civil protection chief Franco Gabrielli maintained the "Level 2 alert" until at least 1700 GMT on Sunday.

He said 54.5 million euros had already been allocated to the reconstruction of roads, bridges, homes and warehouses destroyed last week in the area.

The rain drifted north to the Piedmont region Sunday, where Gabrielli said he was alarmed by the rising waters of the Po river in Alessandria, warning that floods could be expected Sunday night.

The weather alert also affects other parts of Tuscany, the outskirts of Rome and areas in the south of the peninsula, from which Sicily and the Aeolian islands were inaccessible due to strong gusts of Sirocco.