Brent ended with a loss of 1.37% at 51.09 dollars and WTI finished down 1.85% and returned below 48 dollars.

Oil prices fell on Monday after reaching their highest levels in ten months earlier in the day, a sign of optimism during an Opep+ meeting that put off its decision on February's production level until Tuesday.

The barrel of North Sea Brent for delivery in March lost 1.37 percent or 71 cents to 51.09 dollars.

At the start of the day in London, it had reached 53.33 dollars, a price most seen since March 3, 2020.

For its part, the American barrel of WTI for the month of February fell 1.85% or 90 cents to 47.62 dollars, after having nevertheless climbed to 49.83 dollars, close to the 50 dollars mark that it has not crossed since February 26 last year.

Investors and market observers had their eyes on the ministerial summit of members of the Organization of Petroleum Exporting Countries (OPEC) and their allies via the Opep+ agreement, which began by videoconference around 15:30 GMT (16:30 in Paris).

But the participants decided on Monday to postpone their decision on February's production level until Tuesday, after three hours of videoconference discussions.

“Crude prices face several risks at the start of the year, the main one being that of seeing an Opp+ group being too aggressive in putting more crude on the market,” explained Edward Moya, an analyst at Oanda.

Despite Saudi Energy Minister Abdulaziz bin Salman's cautious speech at an online press conference shortly before the meeting on Monday, some investors now expect the producer group to open its crude oil tap again next month, a step perhaps premature as the recovery in demand remains uncertain.

At the beginning of December, the alliance countries decided to increase their production, which they voluntarily limit, by only 500,000 barrels per day, to avoid flooding the market with the two million barrels per day initially planned.