MOSCOW (AFP) - Russian authorities said on Thursday (Aug 26) they were close to putting out the devastating forest fires that have ripped across Siberia this summer in what environmentalists have linked to climate change.

In hard-hit Yakutia - Russia's largest and coldest region - wildfires have burned through 99,000 sq km, an area larger than Portugal.

Smoke from the fires in the sparsely populated region that sits atop permafrost reached the North Pole earlier this month, Nasa said.

By Thursday the fires were active in an area of around 5,200 sq km, according to Russia's forestry agency, as the region experienced rainfall and a drop in temperatures.

"The president instructed us to extinguish the fires in Yakutia. This task is almost complete," the deputy head of Russia's emergencies ministry, Alexander Chupriyan, said on Thursday.

He added that the remaining fires were under "control", the Tass news agency quoted him as saying.

While wildfires affect Russia every summer, in recent years they have ripped through the country's vast forests with growing intensity.

So far this year, blazes have ravaged over 173,500 sq km, making it Russia's second-worst wildfire season since the turn of the century.

President Vladimir Putin on Tuesday pledged hundreds of millions of dollars to protect the country's forests, saying the nation must "learn lessons" from this year's fires.