The head of the Republic of Sakha, a region also known as Yakutia, wrote on the Telegram messaging app that more than 110 forest fires were raging across about 61,000 hectares, roughly three-quarters the size of New York City.

"In recent days, there has been intense heat, thunderstorm activity has intensified, which is the reason for the situation’s complexity," Aisen Nikolayev wrote.

The Interfax news agency reported that 620 personnel and 33 ground vehicles and planes were involved in extinguishing the blazes. There were no immediate threats to settlements, it said. The population of Sakha, Russia's largest region by land mass, is roughly one million.

Sakha has tripled its budget for fighting fires this year, Nikolayev told President Vladimir Putin in May.

Wildfires have become more intense in Russia in recent seasons, helped by unusually high temperatures in Siberia, driven by climate change. They release millions of tonnes of carbon and other pollutants into the atmosphere each year.

The 2021 fire season was Russia’s largest ever, with 18.8 million hectares of forest destroyed, according to Greenpeace Russia - about two times the size of the island of Ireland.

Bordering on the Arctic Ocean in the north, Sakha is particularly prone to extreme weather. The 2021 fires there set emissions records and saw wildfire smoke reach the North Pole for the first time in recorded history.

Last year, fires killed over a dozen people across Siberia.

Environmentalists have warned that wildfires may hasten the thaw of Siberian permafrost and peatlands, releasing carbon stored in the frozen tundra into the atmosphere.