The rouble is at risk of increased volatility because of unpredictable oil prices, according to Russia's Central Bank.

With crude oil remaining the country's chief export, the bank issued the warning as it cut interest rates by 25 per cent - a move intended to stimulate lending.

The cut to 10.50 per cent marks the sixth such drop since April, reports Reuters.

"Further steps on lowering interest rates will be determined by the development in inflationary trends, the dynamics of manufacturing and credit activity," the Central Bank said in a statement.

On Friday (11th September), the bank's first deputy chairman Alexei Ulyukayev told the news provider he did not foresee "big fluctuations" in the rouble between now and the end of the year.

Meanwhile, Russian finance minister Alexei Kudrin predicted this week that "fundamentals will allow the rouble to be fairly stable".

The currency reached a six-week high of 36.98 against the euro-dollar basket on Friday and closed at 37.21 on Monday (14th September).

Mining tycoon Vladimir Potanin has claimed a short-term weakening of the rouble is in the interest of Russia's economy and export firms as it will help them bring down costs while the economy picks up.