The world oil market dipped Friday after rallying on the back of the first drop in US stockpiles for six months as well as a weaker dollar.
Brent North Sea crude for June delivery lost 42 cents to stand at $66.36 a barrel in London just after midday.
US benchmark West Texas Intermediate for delivery in June shed 11 cents to $59.52 a barrel.
However, trading was quiet with most Asian markets closed for public holidays, and many European players also away for a long May Day weekend.
Prices had rallied Thursday on data suggesting the US crude glut is easing as the dollar weakened against the euro.
Both contracts rose by about a fifth through April owing to several factors, including concerns about unrest in Yemen, the weakening dollar and fewer US rigs in operation to produce the black gold.
However, prices remain well down after plunging almost 60 percent between June and January on the back of a global supply glut and ramped up production.
The latest jump came after Wednesday's US Department of Energy inventory report, which showed a 500,000 barrel drop in petroleum stocks to 61.7 million barrels at the key Cushing, Oklahoma trading hub.
While the decline was modest, it marked the first drop since late November. Traders are taking the decline as a sign producers are cutting back at key US petroleum sites, such as the Bakken region in North Dakota, analysts said.
However, Ric Spooner, a chief strategist at CMC Markets in Sydney, told Bloomberg News: "The market appears to be happy enough with steady production levels and the reduction in inventory.
"It's likely that the gains that we've seen might be getting close to an end point. Oil will probably find it difficult to sustain values much beyond the mid $60s."