Smog from fires smothers Moscow
Dozens of flights had to be diverted from Moscow because of dense smog from wildfires shrouding the city.
Runway visibility was down to as little as 220 yards at times, while in central Moscow it was a few dozen yards.
Airborne pollutants such as carbon monoxide were four times higher than average readings - the worst seen to date in the Russian capital.
Kremlin spires and church domes disappeared into the dirty mist, which was forecast to hang around for days due to the lack of wind.
More than 500 separate blazes were burning nationwide on Friday, mainly across western Russia.
Dozens of forest and peat bog fires around Moscow have ignited amid the country's most intense heat wave in 130 years of record-keeping.
"All high-temperature records have been beaten, never has this country seen anything like this, and we simply have no experience of working in such conditions," Moscow emergency official Yuri Besedin said. He added that 31 forest fires and 15 peat-bog fires were burning in the Moscow region alone.
At least 52 people have died and 2,000 homes have been destroyed in the blazes. Russian officials have admitted that the 10,000 firefighters battling the blazes are not enough - an assessment echoed by many villagers, who said the fires swept through their hamlets in minutes.
To minimise further damage, Russian workers have removed explosives from military facilities and were sending planes, helicopters and even robots to help control blazes around the country's top nuclear research facility in Sarov, 300 miles east of Moscow.
A wildfire leapt into a Russian naval air base outside Moscow last week, causing substantial damage with up to 200 planes destroyed. The forecast for the week ahead, with temperatures approaching 38C shows little change in Moscow and surrounding regions, where the average summer temperature is around 23C.