A rampant heat wave has hit some European countries recently, and more wildfires have been reported.

In the latest development, Spanish Authorities on Sunday announced a "slight improvement" as they enter the fourth day of their battle to contain a wildfire in the Sierra de Gata hills in southwest Spain.

The fire, which is in the region of Extremadura, has consumed around 6,500 hectares of land and led to 1,400 people being evacuated from the towns of Acebo and Perales del Puerto in the early hours of Friday morning.

The first three days of the fire had seen high. Changeable winds produce difficult conditions for the hundreds of firefighters who came from Extremadura, and other Spanish regions, such as Andalusia, Castilla-Leon, and even neighboring Portugal.

Those winds died down late on Saturday allowing firefighters to work "without stopping" to create firebreaks and control the flames.

The work carried out by around 300 firefighters means that all of the roads in the region are now open, although residents from a third town Hoyos have still not been able to return homes and the Red Cross maintains an operation to look after a total of up to 2,000 possible evacuees.

Investigations continue into how the fire started.

Spain's Ministry of Agriculture and Environment confirmed on Friday that the first seven months of 2015 had seen 52,227 hectares destroyed by fire: over twice the 20,947 hectares burned in 2013 and well above the 37,584 hectares affected last year.

The Spanish Meteorological Agency AEMET confirmed on Thursday that Spain experienced the hottest July since records began using the current system in 1980.

Meanwhile, a Red warning code was issued in Bulgaria over wildfire danger on Sunday, the National Institute of Meteorology and Hydrology of the country with the Bulgarian Academy of Science announced.

The National Institute of Meteorology and Hydrology warns citizens to be vigilant and ready to take actions in case of a fire that spreads fast.

Bulgarian Deputy Minister of Agriculture and Food Georgi Kostov said on Saturday preventive measures against forest fires should be taken by the ministry and the Executive Forest Agency.

He said,"Some 8,000 decares of forest territories have been affected by fire in the country so far during this fire season."

The official recalled tackling the damages caused by a fire on 1 decare cost over BGN 2,000 (about 1,200 U.S. dollars), which meant so far about BGN 16 million (about 10 million dollars) had been spent.

Some 11,000 decares of forest territories were affected by fire on the average each year in Bulgaria, a Balkan country with 70 percent mountainous territory.

The reported 8,000 fire-affected decares so far in 2015 is about two-thirds of this figure and the country is only a month into the fire season, which ends at end-October.

The recent heat wave has also caused more people feeling uncomfortable in central Europe, such as Slovakia, Austria.

Paramedics went out on a call to rescue people in Slovakia collapsing from heat 729 times total between Monday morning and Friday evening, confirmed Jozef Minar of the Slovak Emergency Medical Service Operational Center on Saturday.

Statistics were ratcheted up significantly by Friday, when paramedics had to treat 110 heat-induced collapses.

Heat warnings in Slovakia are still in place, as peak temperatures ranged between 35-37 degrees Celsius.

According to the Slovak Hydrometeorological Office, temperature peaks are forecast to reach up to 38 degrees Celsius at some locations on Sunday and Monday, prompting Hydrometeorological office to issue the highest third-level heat warning for southern and southwestern Slovak regions.

According to earlier reports, the month of July has also been the hottest in Austria in the 248 years since temperatures have been recorded, the Central Institute for Meteorology and Geodynamics (ZAMG) said.

Two heavy heat waves that took maximum temperatures up to 38 degrees Celsius are largely responsible, according to ZAMG climatologist Robert Klonner, who said the temperatures across the country were three degrees hotter than the long-term average for the month.

Klonner said in some parts of the country it was not only the hottest July on record, but the hottest month ever recorded.

The number of hours of sunshine for the month was also a significant 20 percent higher than the long-term average across the country, while 20 percent less rain than average was recorded.