Brent crude futures climbed $1.16, or 1.8%, to $66.34 a barrel by 0430 GMT, after hitting the lowest level since May 21 of $64.60 earlier in the session
On Monday, China reported 125 new COVID-19 cases, up from 96 a day earlier. In Malaysia and Thailand, infections continue to hit daily records of more than 20,000
Under existing curbs, OPEC, led by Saudi Arabia, and non-OPEC producers, led by Russia, have cut just over 7 million barrels per day (bpd), while Saudi Arabia has made an additional voluntary reduction of 1 million bpd.
The market has drifted lower over the past few days as more European countries pause inoculations of AstraZeneca's COVID-19 vaccines due to concerns over possible serious side effects, which could slow a recovery in fuel demand.