ZAGREB, Croatia (AP) — A Croatian firefighter has died during a deadly storm that swept the Balkans after a heatwave, brining the death toll to six, officials said Thursday.

Emergency services in Slovenia, Croatia, Bosnia and Serbia scrambled Thursday to restore electricity and clear the debris left over after Wednesday's chaos.

Meteorologists said the storm was extremely powerful as it was formed after a string of very hot days. Experts say extreme weather conditions are likely fueled by climate change.

Elsewhere in Europe, a continuing heat wave caused wildfires and public health warnings.

Throughout the Balkan region, authorities reported hundreds of injured, including some seriously, from fallen trees, roof parts or other object blown off by the swirling winds.

The firefighter in the eastern Croatian town of Tovarnik died "tragically' during the storm, the his unit said, revealing no other details.

Three more people died on Wednesday in Croatia, one in Slovenia and one in Bosnia. Serbia's police said emergency crews saved 40 people and put out 20 fires caused by thunder and lightning.

Tens of thousands of people also have been left without electricity in Slovenia, Croatia and Serbia. The town of Sremska Mitrovica, in northwestern Serbia, imposed emergency measures, saying the damage is huge, including damaged roof over the surgical wing in the local hospital.

Emergency measures are usually declared for floods or similar natural disasters to enable local authorities to draw more funds and people during a crisis situation.

Authorities have warned that more storms are possible in the next few days before the next wave of very hot weather begins.