Russia on Friday launched a national response centre and deployed additional firefighters to battle record-setting wildfires tearing through its coldest region of Yakutia in Siberia.

While Siberia sees an annual wildfire season each summer, the fires have burned with an increasing intensity in recent years, which Russian weather officials and environmentalists have linked to climate change.

In Yakutia, one of the hardest-hit regions this year, fires have already burned through more than 9.4 million hectares (23.2 million acres) -- an area larger than Portugal -- according to Russia's forestry agency.

The emergencies ministry said it had launched a national response centre to fight the blazes in Yakutia -- a sparsely populated region nearly five times the size of France -- saying that it would handle day-to-day management.

It added that it had sent another 200 specialists to support the more than 5,000 people currently battling the blazes in the region.

On Thursday, emergencies ministry officials arrived in Yakutia to oversee operations there on the orders of President Vladimir Putin, who also ordered reinforcements to fight the fires.

Fires in Siberia have burned with an increasing intensity in recent years
Fires in Siberia have burned with an increasing intensity in recent years RUSSIAN EMERGENCY SITUATIONS MINISTRY / Handout

Heavy smog hung over the regional capital of Yakutsk on Friday, which was declared a non-working day in much of the region over health concerns due to wildfire smoke.

"It's very bad, there's a lot of smoke, it's difficult to breathe," resident Yevgeniya Bubyakina, 87, told AFP.

"It is a serious catastrophe," 16-year-old Yelizaveta said.

Some 3,800 kilometres (2,300 miles) to the southwest in the Urals region of Chelyabinsk, the ecology ministry said that it was seeing a higher than normal level of toxic hydrogen sulfide as a result of smog that had travelled from Yakutia.

It recommended that residents keep their windows closed at night, the TASS news agency reported.

Nationwide, wildfires have scorched around 16.6 million acres, quickly approaching Russia's record fire season this century when 18.1 million acres burned in 2012.