Southern Italy continued to bake in sizzling heat on Monday, with temperatures exceeding 40 degrees Celsius in some regions.
The heat wave pushed temperatures up to almost 36 degrees in Rome, making it the hottest day this month in the capital.
World Health Organisation official Roberto Bertollini warned that such heat in a major city like Rome could cause up to two deaths a day.
"More fatalities than that can be expected if the temperature goes up 2 or 3 more degrees," said Bertollini, stressing that the elderly were the most at risk followed by young children.
The civil protection department issued heat warnings for five other cities, all in the south, urging the elderly and children to stay indoors as much as possible during the hottest hours of the day.
Sicily and Calabria were the worst hit southern regions, with emergency services flooded by calls from people suffering from the heat.
In the Sicilian port cities of Catania and Siracusa, temperatures rose to almost 45 degrees by mid-afternoon while several blackouts were reported in Palermo, caused by overheated cables and a spike in energy consumption fuelled by the use of air conditioning.
Some Sicilian factories including a major Fiat plant were forced to shut down for the day.
Meanwhile, firefighters were battling forest fires caused by the heat.
Near Palermo, strong winds increased the risk of fires spreading and several homes and a hotel had to be evacuated.
Local TV stations were also affected after the heat damaged electricity cables.
The heat triggered a protest by a dozen bus drivers in Palermo, who refused to drive their vehicles because they lacked air conditioning.
