Italy declared a state of emergency on Tuesday after flash floods on the island of Sardinia left 17 people dead and forced hundreds to seek emergency shelter as the waters swept away bridges and flooded homes.

   Several people were still missing and emergency workers were trying to access low-lying rural areas affected as the Mediterranean cyclone swept through on Monday, with officials saying some 20,000 people were affected.

   Soldiers were deployed in the region and the government promised to send 20 million euros ($27 million) in emergency funds, as local rescue services said their efforts were being hampered by damage to roads.

   "We are focusing on essential operations: saving human lives, assisting displaced people and clearing road access," Prime Minister Enrico Letta said at a press conference after an emergency cabinet meeting.

   "This was an absolutely extraordinary event," Letta said, following

criticism from local residents in Sardinia who complained about not receiving enough warning about the strength of the storm.

   The port city of Olbia, a popular holiday destination in the summer months, was left almost entirely under water and hotels, sports halls and residents on the island put up people displaced by the flood.

   "The number of victims has risen to 17 and several people are missing," regional governor Ugo Cappellacci said on news channel SkyTG24, with Italian media quoting other officials saying four were missing.

   Olbia's mayor Gianni Giovannelli said: "We found the body of a boy this morning after searching for him all night. This is an extremely painful process."

   Among the dead was an entire family of four Brazilians who drowned in their basement flat in the town of Arzachena in the northern part of the island.

   Three people from another family also died when a road bridge collapsed onto their van near Olbia, while a mother and daughter were found dead in a car that was swept away in the city by surging waters.

   A 64-year-old woman died in her flooded home in Uras in the southwestern

part of the island, while her husband was hospitalised suffering from

hypothermia.

   The heavy rain and high winds meanwhile shifted to the regions of Calabria and Campania in southern Italy and officials said they were monitoring the level of the River Tiber in Rome to check that it does not overflow.

   The holiday village of Sellia Marina in Calabria had to be evacuated and ferry services from Naples to the islands of Capri, Ischia and Procida were disrupted.

   In Sardinia, Gianfranco Galaffu, a local director of the civil protection agency, told AFP that "around 20,000 people" had been affected by the flooding.

   "We are still trying to reach some parts of the lowlands. There could be more victims in their cars... But the worst of the emergency is over," he said.

   Silvio Saffioti, head of the fire brigade for Sardinia, said that "many pump trucks" to remove floodwaters were themselves stuck in flooded areas and he was waiting for more equipment to arrive from the mainland.

   The fire brigade said they had carried out 600 rescue operations between Monday and Tuesday and Saffioti said that rescue dogs were also being used and that army and navy units were providing personnel and equipment.

   Civil protection agency chief Franco Gabrielli said the island was

"unprepared" for the flooding, caused by 440mm (17.3 inches) of rain in the past 24 hours alone -- almost half the amount that usually falls on average in Italy over an entire year.

   "We are only just starting the rescue effort. I have found a lot of

willingness, a bit less organisation," Gabrielli was quoted by Italian media as saying after flying into Olbia to oversee the rescue operations.

   Paola Pagliara, a hydro-geological risk expert at the civil protection agency, told AFP there had not been a storm of this intensity in Sardinia “for centuries.”

   "Everything was done correctly in terms of forewarning. We issued a red alert of maximum emergency not only over the risk of rain but also of flooding," she said. (AFP)