Oil prices fell slightly on Monday as rising COVID-19 infections in India and other countries prompted concern that stronger measures to contain the pandemic would dent global growth.
Brent crude for June settlement dipped 21 cents, or 0.3 percent, to $66.56 per barrel, after having climbed 6 percent last week.
U.S. oil futures were down 14 cents, or 0.2 percent, at $63.05 on worries over fuel demand recovery amid rising virus cases.
The overall global Covid-19 caseload has topped 141.1 million, while the deaths have surged to more than 3.01 million, according to Johns Hopkins University.
The U.S. is the worst-hit country with the world's highest number of cases and deaths at 31,668,532 and 567,217, respectively, according to the University's Center for Systems Science and Engineering (CSSE).
In terms of infections, India follows in second place with 14,788,109 cases. India reported 2,73,810 new Covid-19 cases and 1,619 deaths in the last 24 hours, according to data from the Union Health Ministry.
Hong Kong late on Sunday said the Asian financial hub will suspend flights from India, Pakistan and the Philippines from Tuesday due to imported coronavirus infections.
Japanese health authorities are concerned that variants of the coronavirus are behind the country's emergence of a fourth wave.
In South Korea, health authorities have warned of a possible fourth wave and tougher Covid-19 restrictions if infections do not slow down fast enough.