The CEO of Lukoil, Russia's largest private oil company, told a conference on Friday that oil could go as low as $25 a barrel.

Speaking at the Gaidar Economic forum in Moscow, Vagit Alekperov said that the volatility in oil markets was so extreme that he could not rule out further sharp falls.

"Yesterday they fluctuated by 10%. This has never happened, " Alekperov said.

Crude oil prices have sunk by more than 50% since June last year. Over that time Brent crude has dropped from a high of $117 a barrel to under $50 a barrel on Friday.

As evidence for his concerns Alekperov cited the stance of Saudi Arabia. Last month Saudi oil minister Ali al-Naimi hinted that the kingdom would not act to prop up crude markets even if the price fell as low as $20 a barrel.

"As a policy for OPEC - and I convinced Opec of this, even Mr al-Badri [Opec secretary general] is now convinced - it is not in the interest of Opec producers to cut their production, whatever the price is.

"Whether it goes down to $20, $40, $50, $60, it is irrelevant," the BBC reports him as saying.

Lower oil prices would pose an even greater headache for the Russian government, with the country already reeling from the impact of the price drop and international sanctions. Speaking at the Gaidar conference earlier in the week Russian Finance Minister Anton Siluanov estimated that at $50 a barrel, Russia's federal budget will lose 3 trillion rubles ($45.4 billion) in revenue.

Oil and gas account for around 10% of Russian GDP and, due to windfall taxes on the sector, around half of government revenues. If the oil price remains at current levels through 2o15, the government will be required to institute 10% cuts to all departments other than defence, he said, and may have to take 500 billion rubles out of the reserve fund in order to cover the rest of the losses.

At $25 a barrel, all bets on the Russian economy would be off.