Russian President Vladimir Putin has ordered the army to help tackle massive wildfires raging in Siberia and other regions in the east.
The decision was taken after Mr Putin was briefed on the growing crisis by the head of the emergencies ministry.
About three million hectares (7.4 million acres) have been affected, in what Greenpeace is describing as an "ecological catastrophe".
Many local residents say not enough is being done to tackle the fires.
More than 700,000 people have signed a petition calling for tougher action and for an emergency to be declared across the vast Siberia region.
There has been widespread anger after comments by emergencies officials that they are not planning to tackle wildfires in remote uninhabited areas because there is no direct threat to people.
What's the latest situation?
On Wednesday, President Putin ordered service personnel of the defence ministry to join in the firefighting efforts in Siberia.
Ten planes and 10 helicopters with firefighting equipment are being deployed in the region.
A state of emergency was earlier declared in the Irkutsk and Krasnoyarsk regions, two areas of the Republic of Buryatia and one area of the Republic of Sakha (Yakutia).
On Wednesday Prime Minister Dmitry Medvedev flew in to Krasnoyarsk city to chair a crisis meeting with local officials.
"The most important task is to prevent the fire from spreading to populated areas," he said.
He said everything had to be done to avoid a wildfire disaster like the one that hit Russia in 2010, when "practically the whole country was burning, and there were dozens of dead".
Last week, Greenpeace Russia tweeted that "big Siberian cities are covered with toxic haze that had already reached Urals".
The organisation estimated that 3.3 million hectares were burning across Russia, adding that this was bigger than territory of Belgium.
Ecological catastrophe in Russia: wildfires have created over 4 million sq km smoke lid over central northern Asia. Big Siberian cities are covered with toxic haze that had already reached Urals. #потушитепожарывсибири #stopfires #stopclimatechange #GreenpeaceFire pic.twitter.com/inNSOnOGvv— Greenpeace Russia (@greenpeaceru) July 26, 2019
The acrid smoke has affected not only remote villages and small towns but major cities such as Yekaterinburg and Chelyabinsk.
Wildfires in Russia have been raging for weeks, caused by record high temperatures combined with lightning and strong winds.