Oil prices fell on Thursday, paring recent gains, as renewed lockdowns and the emergence of new coronavirus variants weighed on prospects for a swift demand recovery.

Brent crude fell $0.52, or 0.9%, to $60.95 a barrel by 1122 GMT and US West Texas Intermediate crude lost $0.48, or 0.8%, to $58.20.

The Brent benchmark had risen in the previous nine sessions, its longest sustained period of gains since January 2019. Wednesday had marked the eighth daily gain for the US crude.

 “The rally that has been on until Wednesday’s close may take some time to be repeated as finally the reality is being priced in, namely the slow pace of oil demand recovery,” said Rystad Energy Head of Oil Markets Bjornar Tonhaugen.

The International Energy Agency (IEA) on Thursday said that global oil supply is still outstripping demand because of Covid-19 lockdowns and the spread of virus variants.

 “The forecasts for economic and oil demand growth are highly dependent on progress in distributing and administering vaccines, and the easing of travel restrictions in the world’s major economies,” the IEA said.

The market has been driven higher recently as the Organisation of the Petroleum Exporting Countries (OPEC) and its allies, a group known as OPEC+, reduced output and Saudi Arabia pledged additional voluntary cuts.

But the IEA said that a rapid stock draw expected in the second half of the year could set the stage for OPEC+ to start unwinding its cuts.

Further price pressure came from the end of a blockade by Libya’s Petroleum Facilities Guards at the port of Hariga. The stoppage at Hariga began last month and contributed to a decline in Libyan oil output.

Argentina’s oil output also started to rise, pressuring prices.

However, US crude stockpiles fell last week for a third straight week, dropping by 6.6 million barrels to 469 million barrels, the lowest level since March, the Energy Information Administration said. Analysts in a Reuters’ poll had forecast an increase of 985,000 barrels.

Yet the continuous struggle caused by the emerging variants of the virus and doubts about the efficacy of vaccines continue to dampen sentiment.

A UK scientist said the coronavirus variant found in the British county of Kent is likely “to sweep the world” and could undermine the protection given by vaccines.