Death rates rose by more than a quarter in Russia in August during an unprecedented heatwave that sparked forest fires across the country, official statistics showed Thursday.

Amid record temperatures and rampant wildfires, the death rate nationwide shot up 27.4 percent in August compared with the same month last year, the state statistics office said in figures published on its website.

The surge saw 41,262 more people die than during August 2009, while the previous months' figures showed no significant rise year-on-year.

Moscow alone saw 9,000 more deaths in August, or a 68.6 percent hike in the mortality rate, as residents inhaled a toxic mix of smog and smoke from nearby forest and peat-bog fires.

The Russian authorities have faced strong criticism for downplaying the health risks amid the country's worst ever heatwave.

The health ministry only acknowledged on August 30 that the country had seen a spike in deaths in the affected regions -- despite media reports this summer that described morgues as overflowing.

Federal authorities initially refused to give details of the Moscow death toll and there was no public announcement of the figures.

The authorities have partially attributed the rise in deaths to an increased number of drownings as Russians rushed to escape the sweltering temperatures topping 40 degrees Celsius (104 Farenheit) over several weeks.

Officials say it may take months for the government to tally the damage from the disaster that destroyed over a quarter of the grain harvest, but several economists have put the cost to the economy this year at 7-15 billion dollars.