Europe's unprecedented early summer heatwave may be responsible for hundreds of excess deaths, according to the head of the World Health Organization (WHO).

Temperature records were broken across the continent again on Sunday – including in Germany, Poland and the Czech Republic – as the extreme heat continued to move east.

In a post on X, WHO chief Tedros Adhanom Ghebreyesus said more than 1,300 excess deaths had been recorded since 21 June "linked to high temperatures in Europe".

"Heat stress is often called the 'silent killer' - and European homes, workplaces and schools were not built for these temperatures," he said.

On Sunday morning, France's national health ministry said there had been around 1,000 more deaths than expected in the country since Wednesday.

Many of the extra fatalities are among those aged 65 over, the agency said, after logging a 40% rise in the number of people dying at home.

"Europe is the fastest-warming continent on Earth, heating at twice the global average," Tedros warned.

Millions of people across the continent are currently "living under extreme heat, hundreds have died, schools are shut, grids are buckling", he added.