Russia has mobilised about 250,000 people to fight hundreds of wildfires scorching through a vast areas of in the country, as soaring temperatures and high winds continue to fan the flames.
At least 40 people have died in fires in the past week and seven regions are under a state of emergency.
No let-up in the record heatwave is expected in the next few days, with temperatures in the Moscow area expected to hit about 38 degrees Celsius.
President Dmitry Medvedev has described the situation as a "natural disaster of the kind that probably only happens every 30 or 40 years".
Smoke and flames continue to spread across the western and southern regions of Russia, with almost 400 new fires breaking out since Saturday, the BBC reports.
Those monitoring the growing disaster from the air say many fires are the result of people being careless during the heatwave.
They say many tourists are making fires and leaving behind rubbish, including glass bottles which can often cause fires in hot weather as they work like a magnifying glass.
The fires have destroyed whole villages, leaving thousands homeless and a growing number of casualties.
Officials say a naval aviation storage area outside Moscow has been destroyed, with the loss of an unknown quantity of hardware.
According to the Russian news agency Interfax, the Kolomna depot services aircraft from all of the Russian navy's fleets.
Elsewhere, extra firefighters are protecting a major nuclear facility at Sarov, in the Nizhny Novgorod region.