PARIS, France (AFP) — French health officials said on Tuesday that there were at least 300 more deaths than expected during a five-day heatwave in May, the country’s first of the year.

“We recorded 300 excess deaths, corresponding to an increase of nearly 14 percent,” said Caroline Semaille, director general of Public Health France, adding that the deaths were due to all causes combined and were not necessarily linked to elevated temperatures.

The May heat episode, “characterised by its early timing and intensity compared with seasonal norms, exposed a population not yet accustomed at that time of year to high temperatures, during a period when school and work activities are still in full swing,” the public health agency said.

Apart from the May heatwave, France experienced a record-breaking heatwave of 11 days earlier this month that scientists link to climate change.

The latest episode of extreme temperatures disrupted life in France, where few homes are equipped with air-conditioning units, and most schools are not designed to cope with extreme heat.

Citing preliminary figures, health officials on Sunday said they registered around 1,000 more deaths than during the same period in previous months since Wednesday last week, when France was at its hottest since records began.

Prime Minister Sebastien Lecornu said on Monday that more people had died in their homes during the latest heatwave than in previous episodes.

Heatwaves typically cause between 1,000 and 7,000 deaths per year, and “this summer we may be closer to 7,000 than to 1,000”, epidemiologist Basile Chaix of French research institute INSERM told AFP.