"The alert remains high across the country," fire services spokesman Luca Cari told AFP earlier. "We have doubled the personnel rotations to ensure a stronger presence … and we have transferred personnel from the north of the country to the south to help us."
In Romania authorities said the heatwave-related death toll rose to 33 with three more people succumbing on Tuesday.
In the capital Bucharest where temperatures reached 37 degrees Celsius (99 Fahrenheit) more than 170 people fainted in the street. Ambulance services received a record of more than 1,200 calls over the past 24 hours, according to the Mediafax news agency.
Power flickered on and off in Bucharest where air conditioners were working overtime.
Some 30 people died in a heatwave last month in Romania.
In Slovakia a lightning strike sparked a huge forest fire on Sunday that was still raging across about 10 hectares of the Slovensky Raj (Slovakian Paradise) national park in the east of the country.
©AFP – Gent Shkullaku
Meanwhile the mercury reached 46 degrees Celsius (115 F) in parts of Greece, where a dozen forest fires were burning and up to five people have died from heat-related causes since Monday.
Authorities set up air-conditioned shelters in Athens and Greece’s second largest city Salonika, while fire forced the evacuation of a monastery, a village and a summer camp near the southern town of Aigion.
Another fire on the Ionian island of Kefalonia threatened some nearby towns, firefighters said.
Greeks were warned to stay indoors and help conserve electricity between 11:00 am and 3:00 pm to prevent power outages.
"Until (Wednesday evening) when the heatwave passes, we ask for restraint," Interior Minister Prokopis Pavlopoulos said, adding: "We don’t need to have the air-conditioning on all day long."
©AFP – Mario Laporta
The heatwave caused a spike in smog pollution in Athens, with ozone levels above emergency limits in several districts, prompting the government to urge motorists to avoid the city centre. Ozone levels were not expected to improve on Thursday.
The fire department said 99 blazes had broken out around Greece since Tuesday, added to hundreds of fires that have burned thousands of hectares of forest and agricultural land since a first heat wave last month.
Temperatures in Greece were expected to drop slightly over the next two days.
Hungary, where up to 500 people may have died last week from heat-related causes, enjoyed a significant drop in temperatures overnight with the welcome arrival of a cool front.
©AFP – Gent Shkullaku
Highs on Wednesday did not exceed 28 degrees Celsius (83 F), down from nearly 40 degrees Celsius (104 F) on Tuesday.
A third degree heat alert — the highest ever applied in the country before last week — ended on Tuesday.
On the western edge of Europe, even without a heatwave Portuguese firefighters are battling blazes near Abrantes, about 100 kilometres (60 miles) north of Lisbon, and in the Caldeirao mountains in the south.