A devastating wave of wildfires across Russia could ravage millions of acres of forests and cause worse damage than last year's catastrophic blazes, environmentalists and officials said Thursday.

"We're burning, burning badly," Greenpeace's forestry expert, Alexey Yaroshenko, said. "This year's situation is already much worse than last year's."

In 2010, an unprecedented heat wave triggered fires that killed 55 people, destroyed thousands of houses and torched 2.6 million hectares (6.4 million acres) of forests _ an area slightly larger than Oregon.

This year, three firefighters have died and dozens of wildfires have already engulfed more than 600,000 hectares (1.48 million acres) of mainly Siberian forests _ nearly three times more territory than this time last year, the Emergencies Ministry said.

Greenpeace claimed the Russian government is silencing information about fires, especially about the renewal of peat-bog fires around Moscow that last year cloaked the capital with acrid, toxic smoke.

"There are dozens of them around Moscow," Greenpeace's Grigory Kuksin told journalists. "It's technically impossible to put out some of them already."

Once ignited, peat bogs can smolder for months or years, surviving even heavy rains and snow. While burning, they emit acrid smoke that can aggravate asthma, bronchitis and heart conditions.

Moscow last year was engulfed in a thick blanket of smog that, combined with the intense heat, doubled the death rate.

In the Soviet era, authorities extensively drained numerous peat bogs around Moscow and other cities in western Russia to extract peat for fuel. Once coal and oil replaced peat as fuel, the drained peat bogs were left unattended.

Moscow authorities have allocated some $150 million to flood the peat bogs, but Greenpeace said that little has been done due to corruption and bureaucracy.

"What's been done is a drop in the ocean," Yaroshenko said.

Russia's forestry agency chief played down the threat to Moscow this year, but admitted that a surge in forest and peat-bog fires is imminent.

"The summer will be tense and uneasy," Viktor Maslyakov told journalists.

He said the government should declare an emergency situation in three Siberian regions, where unusually hot and dry weather has caused multiple wildfires.

Russian forests constitute 22 percent of the world's total woodlands, an area larger than the continental United States.

"Our planet has two lungs _ the Amazon rain forest and the Siberian taiga," said Vladimir Gandzha of Russia's Nature Protection Society, the nation's oldest environmental group. "The latter is blazing now."

A top government official accused illegal loggers of starting some of the Siberian fires to conceal the traces of their work.

"They set it all afire _ and covered it all up," Deputy Prime Minister Viktor Zubkov was quoted by the Itar-Tass news agency as saying.