The fall in oil prices from $147 this July to below $50 today has blown a gaping hole in the government's budget calculations. It is now facing a $150bn shortfall in its spending plans - and will have to slash expenditure in 2009.

Today Putin sought to assure hard-up Russians that their social benefits would not be affected, promising a $20bn assistance package. "We will do everything, everything in our power ... so that the collapses of the past years should never be repeated," he said.

The oil slump, however, exacerbates Russia's already severe economic problems. Since May Russian markets have lost 70% of their value. Russia's central bank, meanwhile, has been spent $57.5bn in two months trying to prop up the country's ailing currency.

"If the current trend continues with the government supporting the rouble, oil prices falling and a slowing economy we are going to have a major crisis," said Chris Weafer, an analyst with the Moscow brokerage Uralsib.

He added: "There will be more pressure on the rouble and an extremely difficult first quarter next year." Russia was more vulnerable than other countries because it was still an oil state, and had failed to diversify its economy, Weafer added.

"In terms of the trigger Putin is correct. The bomb came from the US," Weafer said. He added, however: "The shockwaves have hit a much weaker structure than the [Russian] government has acknowledged. The economy is going to hell in a handcart."