Oil prices rose - Tuesday - supported by the weakness of the dollar and the US plan to rebuild its strategic reserves, but the gains were limited by the uncertainty related to the impact of the rise in Covid-19 cases in China, the largest oil importer in the world.
Crude futures rose 0.65% to $80.30 a barrel by 10:35 GMT, after rising also in the previous session.
West Texas Intermediate crude futures rose $1, or 1.31%, to $76.19 a barrel, after rising by 90 cents on Monday.
The market received support from the US plan announced - last week - to buy up to 3 million barrels of oil for the strategic reserve, after the United States this year released 180 million barrels of stock, which is a record.
A weaker US dollar has also supported prices as it makes oil cheaper for holders of other currencies.
Qatar National Bank said - in a note - "Oil prices may witness a further rise, as we expect spot markets to become increasingly tight due to supply restrictions and strong global demand." The bank expected prices to be between $90 and $115 a barrel in the coming quarters.
Edward Moya, an analyst for OANDA, said in a note that there must be clear signs of growing demand for prices to rise.
Crude oil is still on track to record its second monthly loss this December, in light of the continued lack of liquidity levels in the markets, as a result of tightening monetary policies and raising interest rates, especially in the United States and the eurozone.