Brent crude futures fell 28 cents, equivalent to 0.4%, to $ 68.68 a barrel by 09:39 GMT, and US West Texas Intermediate crude futures lost 31 cents, equivalent to 0.5%, to $ 65.32 a barrel.
The two benchmarks recorded their highest levels since mid-March on Wednesday before retreating to close the session unchanged after two days of gains.
Hopes that the second deadly wave of the Corona virus in India will approach its climax today, Thursday, were dashed, with record daily numbers of infections and deaths recorded and as the virus spread from cities to villages in the second most populous country in the world.
The US Energy Information Administration said on Wednesday that US inventories of crude oil fell by far more than expectations last week, with the rise in refinery production and a jump in exports.
Crude stocks fell 8 million barrels in the week ending April 30 to 485.1 million, compared with analysts polled by Reuters forecasts for a drop of 2.3 million barrels.