The World Health Organization's European office has said the heatwave baking Europe has caused over 1,700 deaths in Spain and Portugal alone, calling for joint action to tackle climate change.

"Heat kills. Over the past decades, hundreds of thousands of people have died as a result of extreme heat during extended heatwaves, often with simultaneous wildfires," WHO regional director for Europe Hans Kluge said in a statement.

"This year, we have already witnessed more than 1,700 needless deaths in the present heatwave in Spain and Portugal alone," Mr Kluge added.

The regional director stressed that exposure to extreme heat "often exacerbates pre-existing health conditions" and noted that "individuals at either end of life's spectrum - infants and children, and older people - are at particular risk".

Responding to a query by AFP, WHO Europe explained that the figure is a preliminary estimate based on reports by national authorities, and that the toll had "already increased and will increase further over the coming days".

The true number of deaths linked to the heatwave won't be known for weeks, he said, adding "this scorching summer season is barely halfway done".

"Ultimately, this week's events point yet again to the desperate need for pan-European action to effectively tackle climate change," Mr Kluge said.

The regional head of the UN health body said governments need to demonstrate will and leadership in implementing the Paris Agreement, which set the goal of limiting end-of-century warming to two degrees Celsius above pre-industrial levels - and preferably not beyond 1.5C.

He said that members of the WHO's European region - 53 countries and regions including several in Central Asia - "have already demonstrated that they can work together on urgent threats to global health," and that it was "time for us to do so again."

A woman drinks water near the Trevi Fountain in Rome

Italian heatwave peaks

Italy faced the hottest day of the current heatwave with red extreme heat warnings issued for 16 cities across the country, as firefighters battled blazes up and down the country.

Worst hit is expected to be Milan in the north with temperatures hitting 40 degrees Celsius, while Bologna to its south and the capital Rome could hit 39C, according to official government estimates.

Other major cities under a cautionary heatwave red alert for today and tomorrow by Italy's health ministry include Florence, Genoa, Turin and Verona.

Yesterday, the city of Pavia, just south of Milan, broke a record with thermometers hitting 39.6C.

For three consecutive months - May, June and July - national temperatures have been at least two to three degrees above the seasonal average, and the trend should continue until early August, said national weather website

Along with the heat have come hundreds of fires across Italy in recent weeks. The largest still raging today was in central Tuscany, where 860 hectares had burned since Monday in an area west of Lucca.

Over 1,000 people were evacuated yesterday.

Some, 87 firefighters were on the ground after another night spent battling the flames, helped by reinforcements from the Lombardy and Piedmont regions. Water dumps from helicopters were under way, authorities said.

Prosecutors in Lucca have opened an investigation over the cause of the fire.

The river Po in Somaglia, Italy, amid a worsening drought

More contained was a forest fire that broke out Tuesday near Trieste, in Italy's northeasternmost region of Friuli Venezia Giulia, sending flames and vast plumes of smoke across the border into Slovenia and displacing about 300 people.

The fire - which caused a 15-minute general blackout on Tuesday in the city of Trieste - was now "substantially stable," Deputy Governor Riccardo Riccardi said, adding that a cold front was expected next week.

Authorities had not yet calculated how many hectares had burned.

Firefighters said a female civil defence volunteer died while trying to fight the fire. Local media said she was killed by a falling tree.

Italy's national firefighting corps say they have intervened in 32,921 wildfires from 15 June to 21 July, or 4,040 more than in the same period last year.

Most have been in the southern regions of Sicily, Puglia, Calabria and Lazio, around Rome.

A woman refills her bottle with water from the 'Fontana della Barcaccia' at Piazza di Spagna in Rome

According to the specialised European monitoring service Copernicus, fires have ravaged 27,571 hectares so far this year in Italy.

That damage, however, is still well short of that in Spain, where 199,651 hectares have burned, or 149,324 hectares in Romania. In Portugal, 48,106 hectares have burned, with another 39,904 hectares in France.

Italy is "about to reach the maximum power of the African high pressure zone 'Apocalypse 4800'", said

The name, it said, referred to the thermometre dropping below zero degrees only at altitudes above 4,800 metres (15,748ft) - corresponding to the highest peak of the Alps, at Mont Blanc along the French-Italian border.