The Croatian firefighters, who included a 17 year-old and two 19 year-olds, died on Thursday after being cut off while battling a wildfire in a national park on the Adriatic island of Kornat, the fire brigade said.

Eleven others were rescued and taken to hospital. Five of them were in a critical condition on Friday with second and third degree burns covering 85-95 percent of their bodies, doctors said.

The deaths occurred a day after the leader of another crew of firefighters died of a heart attack brought on by carbon dioxide poisoning while trying to extinguish a forest blaze on the tourist island of Hvar on Wednesday.

Since June, around 13,000 hectares (32,000 acres) of land made dry by a heatwave has been devastated by some 900 fires mainly along Croatia's Adriatic coastline. The wildfire on Kornat was extinguished overnight by an army unit.

Prime Minister Ivo Sanader proclaimed a day of mourning for Monday.

In Greece, hit hardest by the recent fires with at least 63 people dead in eight days, blazes were no longer threatening populated areas in the ravaged Peloponnese peninsula.

"Things are going well," a fire service spokesman said, helped by a drop in winds that had reached 70 kilometres (45 miles) per hour last weekend.

"Today the wind is not strong, so the idea is to win the battle today before the wind picks up."

Firefighters assisted by three water-bombing planes were operating around Mount Parnon in the Peloponnese, while a further four were dropping water on burning forests in the north of the peninsula.

The other area of concern was on the island of Evia north of Athens, although soldiers and firefighters had the blaze there under control.

But temperatures in Greece were set to top 40 degrees Celsius (104 degrees Fahrenheit) at the weekend, raising fears that the current improvement may only be a brief respite.

The wildfires broke out on August 24 following the third heatwave the country had experienced this summer. The flames consumed nearly 200,000 hectares of forest and left thousands homeless.

In eastern Spain, a fire that has devastated at least 2,000 hectares was being brought under control Friday, Environment Minister Cristina Narbona said.

"We hope it will be under control today, given the better weather conditions and the resources we are using," Narbona said during a visit to the affected Castellon region.

The fire, which broke out on Tuesday, was fanned by strong winds over the subsequent two days, forcing some 400 firefighters to give ground and evacuate 120 residents from a village.

Cooler temperatures in Algeria meanwhile helped firefighters bring under control most of the blazes that have killed at least eight people and ravaged huge swathes of forest across the north of the country.

Of the 204 fires detected in the past 48 hours, by midday Friday 10 were still active including three in the Bejaia district, east of the capital Algiers, civil protection service spokesman Mohamed Amokrane Medjkane said.

Algerian forecasters said that cooler weather was expected to spread from the west on Friday and over the weekend but authorities remained on high alert for any new fires.

Six people, including a woman and two children, were found burnt to death Thursday in the Tizi Ouzou district of Kabylie, 110 kilometres east of Algiers, while two children from the same family perished on the Jijel coastline.

The fires had stretched across 23 regions of northern Algeria, fanned by Saharan winds and destroying more than 20,000 hectares of oak, cedar and pine forest made tinder-dry by heatwaves and drought.

Six thousand soldiers and dozens of specialised vehicles helped fight the fires. The north African country has no water-bomber aircraft of the kind used in Greece and elsewhere.