The Urals Regional Center of the Emergency Situations Ministry said the seven-hectare (17-acre) fire no longer posed a danger to residents or businesses.

Efforts to keep the fire away from the town and the All-Russian Scientific Research Center of Technical Physics involved 441 members of the fire and forestry services and the ministries of Interior, Defense and Emergency Situations, as well as 66 emergency vehicles and other equipment.

Another Federal Nuclear Center, in the Nizhny Novgorod Region town of Sarov, was threatened by wildfires earlier in the week.

The regional emergencies ministry center said work to quell the fire was hampered by surrounding wetlands that prevented fire trucks from reaching the blaze.

"In the first half of the day, firefighting was carried out backpack fire extinguishers," it said in a statement. "In all, 100 backpack fire extinguishers were used."

Two Mi-8 firefighting helicopters were also used, dumping 19 tons of water on the blaze.

The ministry said enough personnel and equipment had been deployed to extinguish the fire.

The Snezhinsk nuclear center is administered by Rosatom, the Federal Atomic Energy Agency. It was founded in 1955 and according to its official website is primarily focused on the solution of scientific and technical issues of development and testing of strategic and tactical nuclear warheads and the peaceful use of nuclear and thermonuclear energy.