There were downpours Friday in Moscow after several rainless weeks, but dozens of wildfires, one of them near the country's top nuclear research center, were still burning.

The Emergency Situations Ministry said more than 500 wildfires continued to rage across the country, including 29 around Moscow, adding that about 14,000 firefighters were battling blazes around the capital.

The clouds of suffocating smog have largely dissipated over Moscow, but meteorologists say smoke from burning forests and peat bogs may cover the city again during the weekend if the wind direction changes.

A forest fire has grown in size near the town of Sarov, home to Russia's top nuclear research center, which includes an atomic reactor.

Authorities previously said all nuclear fuel had been removed from the center.

More than 2,600 people and about 200 pieces of machinery are currently involved in fighting the fire at Sarov, a small town 300 km east of Moscow.

On Friday, Prime Minister Vladimir Putin met head of the anti-monopoly agency Igor Artemyev, urging him to quickly punish those who attempt to take advantage of the situation and drive food prices up.

"They'd better act in accordance with the law, or they will face fines that would far exceed the profits they would win from speculation," Putin said.

First Deputy Prime Minister Viktor Zubkov said Russia will keep its grain export embargo unchanged.

The ban, which will be in effect from Aug. 15 to Dec. 31, aims to maintain domestic prices and ensure enough feed grain for the country's cattle herds.

Abnormal drought, which was caused by heat unprecedented in Russia's 130 years of record-keeping, has destroyed 30 percent of the country's crops.

Zubkov said it is necessary to start a "normal marketing process" in the country, which means shipping grain from regions with abundant stocks to regions that have suffered from the drought, including Moscow and St. Petersburg.

U.S. President Barack Obama called Russian President Dmitry Medvedev to express his condolences for the losses Russia has suffered because of recent wildfires.

"The president told President Medvedev that he is monitoring the situation closely, and that the United States is responding to Russia's request for technical assistance in combating the fires," the White House said.

California Governor Arnold Schwarzenegger announced the state will provide protective firefighting supplies to Russia.

"California has one of the best prepared and most experienced firefighting operations in the world. It is important we share our resources with other nations -- the same way they have shared with California in the past," Schwarzenegger said.

Wildfires have been raging across Russia over the past month, killing over 50 people and leaving thousands homeless.