The Russian rouble fell to a record low on Monday amid concerns that the US would impose tougher economic sanctions on Russia over the Ukraine crisis.
The rouble fell to 60.5 against the dollar on Monday afternoon in London, despite efforts from the Russian central bank to stem the fall. The rouble also fell to a record low against the euro currency, reaching 75 on Monday.
The Russian rouble has now lost more than 45% of its value against the dollar, while it has also lost 40% against the euro, since Russia annexed Crimea in March.
That period has also coincided with a dramatic fall in the price of crude oil, a key export for the energy producing country. Russia's government relies on export revenues from oil and gas to fund around half of its annual budget.
Oil prices have fallen at a similar rate to the rouble in recent months, suggesting the slump in oil prices is the key factor behind the fall in the value of the currency.
However, the prospect that the US could pass tougher economic sanctions on Russia has caused the latest devaluation of the rouble.
Since Russian markets closed last week, the US Congress passed a bill that prepared tougher sanctions against Moscow. While US President Barack Obama has yet to sign the bill, and has said he opposes further sanctions against Russia without support from the European Union, the bill still managed to weigh on Russia's beleaguered currency.