The price of Brent crude dipped as much as 3.4 per cent in afternoon trading to $50.43 per barrel, its lowest since the January this year, as the commodities crisis continued to weigh on the market.
The news drove the rouble down 1.67 per cent against the dollar, to $0.01593. Russia's economy is heavily dependent on oil.
Shares in UK-listed oil producers also fell, with BP shares dipping 1.89 per cent to 387.98p, while Shell shares fell 1.05 per cent to 1,841p. On Friday, former FTSE 250-listed Afren became the first major casualty of the rout in oil prices when it called in the administrators.
US benchmark West Texas Intermediate (WTI) ended July on its biggest monthly fall since the 2008 financial crisis during July. Today it was down 2.97 per cent at $47.12 per barrel.
Meanwhile, a closely-watched survey by Baker Hughes published on Friday evening showed US drillers added five oil rigs last week, which was expected to mute prices even further.
The news came as analysts at Bank of America Merrill Lynch warned the price of West Texas Intermediate (WTI) could rise above Brent crude by spring next year.
"Higher Middle East output combined with declining drilling activity in North America could reverse WTI-Brent dynamics in 2016," they said.
"With shale output dropping, US refiners may have to import light crude again to keep up with robust gasoline demand growth. Consequently, WTI may have to temporarily trade above Brent next spring to attract foreign light sweet crude into the US."