Russian firefighters have succeeded in pushing back wildfires while an advancing cold front is expected to finally put an end to a two-month heat wave, officials said on Monday.

There were 500 blazes still burning, but the amount of land on fire was down 15 percent in the 24 hours, the Emergency Situations Ministry said. The area covered by fires around Moscow has nearly halved in size over the past two days,

The heat wave — unprecedented in 130 years of record keeping — has sparked thousands of fires, most of them in western Russia. The heat and acrid smog from the fires that blanketed Moscow for a straight week earlier this month have doubled the number of recorded deaths there.

More than 50 people have died in the wildfires across Russia, and more than 2,000 homes have been destroyed.

Meteorologists say that a cold front advancing from the northwest will hit the Moscow region on Monday, bringing heavy rains and colder temperatures.

The heat wave has raised concerns that wildfires could spread to areas contaminated by the 1986 Chernobyl nuclear disaster and spread radioactive particles over broader territory. The authorities have insisted that all wildfires in the Bryansk region and other Chernobyl-affected areas have been quickly dealt with.

Officials said they are well equipped to combat blazes, but Lyudmila Kolmogortseva, an environmentalist and a regional legislator in the Bryansk region, said that emergency workers in the area lack firefighting aircraft and could do little if the fires spread.

"Almost a million cubic meters of dead radioactive wood pose serious danger if the fires spread," she told The Associated Press. "The forest is practically impenetrable, and we practically have no aviation so we'll have nothing to fight the fires if they spread."

Kolmogortseva said that sporadic blazes in the area covered a total of about 30 hectares (some 74 acres) this summer, but they all have been extinguished before they could spread any radiation.

The regional branch of the Emergency Situations Ministry said Monday there are no fires burning now in the area and radiation levels have remained normal.