Oil came under pressure on Monday on signs a multi-week rally was encouraging a rejuvenation in already bloated U.S. shale supplies.
U.S. light crude closed down 14 cents, or 0.2 percent, at $59.25 a barrel. U.S. crude prices gained on a weekly basis for an eighth straight week last week while Brent had its first profit-taking in five weeks.
Meanwhile, Brent crude futures, the more globally referenced benchmark for oil, fell 40 cents to $65 a barrel. In a sign the market was responding to those gains, rigs for drilling oil in the voluminous Permian shale basin rose for the first time this year after months of cutbacks.