U.S. oil prices fell on Thursday, snapping a three-day rally after notching another 2016 high, as a strong dollar sparked profit-taking in crude futures by investors.
Continuous threats by militants against Nigeria's oil industry and fear of more security incidents that could hit supplies worldwide, however, limited losses in crude.
Brent crude oil futures traded 62 cents, or 1.2 percent, lower at $51.88 a barrel, after setting a 2016 high of $52.86 a barrel earlier in the session.
U.S. crude settled 67 cents lower, or 1.3 percent, at $50.56 a barrel after also hitting a new 2016 high at $51.67.
Profit-taking emerged in crude as the dollar index rose half a percent, its most in three weeks, from jittery global financial markets that sent investors toward safe haven currencies. A stronger dollar makes greenback-denominated oil less attractive to holders of the euro and other currencies.
"So far this looks like a modest technical correction following three days of gains, rather than a major reversal," said Tim Evans, energy futures specialist at Citi Futures in New York.
But analysts also anticipate headwinds for oil in coming weeks as Canadian supplies return after last month's wildfires in Alberta's oil sands region and other oil imports grow as well to slow use in U.S. crude stockpiles.