Bosnian authorities put the entire country on red alert Thursday against a heatwave that has seen the Balkan nation bake in its hottest summer on record, the national weather institute said.

Meteorologist Dzenan Zulum said the months of June, July and August had been the hottest since measurements were first recorded 120 years ago.

In some places, the mercury has soared to 41 degrees Celsius (105.8 Fahrenheit) and temperatures in the capital Sarajevo have in recent days been about seven degrees Celsius warmer than normal.

"We predict a similar temperature for the next two or three days followed by a slight cooling from Sunday," Zulum said.

Farmers say between 50-80 percent of their crops have been damaged in the heatwave, and water distribution to several towns has been disrupted.

Bosnia is also battling dozens of forest fires in the south and east of the country, with many hundreds of hectares (acres) of land burned.