Crude oil prices extended losses on Tuesday, plunging more than six percent amid concerns of receding global growth which may lead to weaker energy demand.

Global benchmark Brent was trading down 6.2 percent, at $50.47 a barrel as of 9:12am GMT. The decline followed an 11 percent weekly downturn for the oil contract. Brent crude is at its lowest level since August 2017.

US crude benchmark West Texas Intermediate (WTI) was down 6.7 percent, settling at $42.53 a barrel. US futures slid to their lowest level since July 2017.

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Both grades of crude are in a bear market, usually defined as a decline of at least 20 percent from a recent peak. They are on track for losses of about 40 percent in the fourth quarter.

Investors flocked to safe-haven assets such as gold and government debt at the expense of crude oil and stocks, analysts say. They explain that the US-China trade dispute and the prospect of a rapid rise in US interest rates have brought global stocks down from this year’s record highs.

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US stocks marked their worst daily declines in history on the trading day before the Christmas holiday, with the Dow Jones Industrial Average and the S&P 500 index recording losses of nearly three percent on the day.

“What’s happening in the stock market is raising fears that the economy is grinding to a halt and thereby will basically kill any future oil demand,” Phil Flynn, an analyst at Price Futures Group in Chicago, told Reuters. “They’re pricing in a slowdown in the economy if not a recession with this drop.”

The fourth-quarter price decline is likely to cause producers to throttle back on their output, he said.

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“We have such a risk-off appetite in the broader markets that crude’s only getting swept up in that sentiment as well,” Matt Smith, director of commodity research at ClipperData, told MarketWatch.

The Organization of the Petroleum Exporting Countries (OPEC) may hold an extraordinary meeting if the oil market fails to get balanced, according to UAE Energy Minister Suhail al-Mazrouei.

OPEC and allies led by Russia agreed this month to cut oil production by 1.2 million barrels per day from January.

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