The benchmark Brent crude traded below $54 a barrel, the lowest since September 2017.
Multiple reports said U.S. President Donald Trump was discussing to remove Jerome Powell from his position as chairman of the Federal Reserve after the central bank announced last week to hike the interest rate for the fourth time this year.
The drops are the latest in a series of big steps down for crude, falling from October 3 Brent prices of $86.29/bbl, while WTI was at $76.24/bbl.
Investors flock to perceived safe-haven assets such as gold and government debt, at the expense of crude oil and stocks.
Adding to concerns about oversupply, the number of active USA rigs for drilling oil rose by 10 in the week ended December 21 to 883, according to a report by General Electric Co's Baker Hughes energy services firm.
Still, oil prices fell on Friday to their lowest since the third quarter of 2017 as global oversupply kept buyers away from the market ahead of holidays over the next two weeks.
USA stocks sank on Monday, with all three major indices erasing more than 2 percent at the close.More news: Yellow Vest protests lose bite as the French prepare for Christmas
More news: No White Christmas For Most Canadians, Weather Network Predicts For 2018
More news: Trump hits Graham over his criticism of Syria troop withdrawal
"Today is going to be a market of very thin liquidity and we don't have strong convictions in such market conditions". "The main input over the weekend has been the continued intervention by Opec members", said Olivier Jakob, managing director at Petromatrix.
"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. Global equities.MIWD00000PUS have fallen almost 9.5 percent so far in December, their biggest one-month slide since September 2011, when the euro zone debt crisis was unfolding.
The price drop has caused US shale oil producers to curtail drilling plans for next year.
Oil prices were mixed in thin trading on Wednesday as the US benchmark rebounded from steep losses in the previous session, even though concern over the health of the global economy continued to overshadow the market in the longer term.
The Organization of the Petroleum Exporting Countries (OPEC) and its Russia-led allies agreed this month to slash oil production by more than the market had expected.
Iraq, Kuwait, the United Arab Emirates, Russia and Saudi Arabia will extend an OPEC agreement for oil production cuts for another six months.
'I think that we can easily do with this surplus and reach market rebalance in one or two months.in the first quarter of next year, he said. The surge in U.S. shale production enabled the country to rank first among the world's oil producers, ahead of Saudi Arabia and Russian Federation.