Prices fell to as low as $46.64, the lowest since November 30. The price recovered somewhat over the course of 2016 to just under $57 by the end of the year.
Late past year, OPEC and top non-OPEC producers agreed to cut production to prop up falling oil prices. However, it was always an open question as to how well the decision would hold up.
OPEC and non-OPEC producers agreed in December to cut supplies for six months, helping lift oil prices to about 55 dollars a barrel after a two-year slump.
The Saudi OPEC governor was speaking by telephone from Vienna where he is attending a meeting of OPEC's governing board along with his counterparts from the 13-country OPEC - which accounts for a third of global oil production. "However I feel it is a bit unusual so close to Opec. meeting where a roll over seems likely", said Oystein Berentsen, managing director for oil trading company Strong Petroleum in Singapore.
The weakness in the oil price worsened on reports that oil nations had appeared to rule out deeper cuts to production. West Texas crude lost 4.9% to $45.48.
Traders are looking forward to an industry report on US crude oil and fuel stockpiles at 4:30 p.m. EDT, to be followed by government data Wednesday at 10:30 a.m. EDT. Brent crude, the standard for worldwide oils, rose 62 cents to $48.68 a barrel in London.
Traders also pointed to soaring U.S. oil output, up more than 10 per cent since mid-2016 to 9.3 million bpd, levels not far off top producers Russian Federation and Saudi Arabia.
"Total U.S. petroleum demand rose to nearly 19.9 mbd and the highest since March 3", he said, reports Reuters.
"Many may view the sub-$50 on Brent as a buying opportunity".
The oil price slide accelerated overnight Thursday after OPEC delegates downplayed the chance that the group and other producing countries (such as Russia) would deepen their output cuts when they meet on May 25.
Iron ore prices fell sharply - on the China's Dalian Commodity Exchange, ore for September delivery lost 7.3% the maximum daily drop, while in Singapore, SGX AsiaClear futures fell as much as 9.1% to $US60.37 a ton.
While OPEC is cutting back to alleviate price pressures, USA fracking companies could jump to capitalize on the windfall as crude oil prices jump back above $50 per barrel - according to some estimates, shale oil producers can get by with oil at just over $50 per barrel due to advancements in technology and drilling techniques that have helped cut down costs.
-Futures fell 2.6 percent to settle at $1,228.60 an ounce.
The break below $50 a barrel will likely prove temporary given that OPEC is widely expected to extend its supply deal at its meeting on May 25 beyond the June expiry date, but analysts say more price weakness can not be ruled out.