A noxious smog from spreading wildfires choked Moscow yesterday as Russia moved to protect military and nuclear sites from the relentless march of its worst ever blazes that have already killed 52 people.

The Defence Ministry ordered the evacuation of missiles from a depot outside Moscow as the authorities warned of the risk of fires reactivating contamination in an area hit by the 1986 Chernobyl nuclear ­disaster.

Moscow residents and tourists, many wearing masks, wheezed as they made their way round the city in the thickest smog to hit the capital since Russia’s worst heatwave in decades broke out in July.

The capital’s most famous landmarks like the spires of the Kremlin towers or the onion domes of Orthodox churches were largely invisible from a distance. Some flights at its Domodedovo international airport were being diverted.

“I woke up this morning, looked out of the window and saw a monstrous situation,” declared President Dmitry Medvedev. “We all want this heatwave to pass but this is not in our hands, it is decided above.”

He called on Moscovites to show patience, although he acknowledged “we’re suffocating, you can’t breathe”.

The Emergencies Ministry said the total area ablaze was down slightly at 179,600 hectares and for the first time it was putting out more fires than were appearing.

The fires have claimed the lives of 52 people, the Ministry of Health said yesterday in an updated toll. The Emergencies Ministry called for volunteers to join the firefighting efforts.

Nasa images have shown the fires are easily visible from space and the US space agency said the smoke had at times reached 12 kilometres into the stratosphere.

A particular worry for the Russian authorities has been fires around the city of Sarov in central Russia which houses the country’s main nuclear research centre. It is still closed to foreigners, as in Soviet times.

The Russian nuclear agency has said that all radioactive and explosive materials have been removed from the centre and the Emergencies Ministry has assured the public it has the situation under control.

The Defence Ministry meanwhile ordered weapons, artillery and missiles at a munitions depot at Alabinsk, about 70 kilometres southwest of Moscow, to be transferred to a secure site.

Military prosecutors said yesterday that a fire on July 29 had destroyed a paratroops base outside Moscow, the second confirmed case of the wildfires hitting a major strategic site.

Mr Medvedev has already warned Russia’s top two naval commanders and sacked a string of officers for failing to halt a fire last week that destroyed 13 warehouses and 17 storage areas at a naval logistics base.

Emergencies Minister Sergei Shoigu said his forces were also working flat out to prevent the fires spreading to the Bryansk region in western Russia where the soil is still contaminated by the Chernobyl nuclear disaster.

“The government should pay a great deal of attention to the protection not only of military bases and science towns but to these places as well,” said Nikolai Shmatkov of the World Wildlife Fund, Interfax reported.