U.S. oil prices rose to near one-month highs on Monday as a weak dollar prompted buying a day before the June contract's expiration, while Brent prices fell as slumping global equities outweighed the impact of low Libyan output.
The U.S. dollar fell to its lowest level in more than three months against the yen, which is supportive for oil and commodities priced in dollars.
Asian and European equities fell after data released late on Sunday showed growth in average new home prices in China slowed to a near one-year low in April.
Meanwhile, Libya's major western oilfields, El Sharara and El Feel, remained shut a week after the government said it reached a deal with protesters to reopen them. National output has been capped at 210,000 barrels per day (bpd), far below the 1.4 million bpd produced until mid-2013.
Heavily armed men stormed the parliament in Libya's capital of Tripoli on Sunday and demanded its suspension, causing Saudi Arabia to close its embassy and the Algerian state energy firm Sonatrach to order its 50 workers to leave the country on Monday.
U.S. crude for June delivery settled 59 cents up at $102.61 a barrel, its highest settlement since April 22, on light trading volume ahead of its expiration on Tuesday. The July contract settled 53 cents higher at $102.11 a barrel.
Brent crude settled 38 cents lower at $109.37 a barrel, having climbed to an earlier intra-session high of $110.33 a barrel on the violence in Libya.
"Libya helped propel the market last night but fell off this morning," said Tariq Zahir, an analyst at Tyche Capital Advisors in New York. "The June contract coming off the board helped U.S. crude because there was not as much volume. Everything was going to the July contract, which is 50 cents lower (than the June contract)."
SUPPORT FROM UKRAINE CRISIS
The conflict in Ukraine kept supporting oil, as U.S. President Barack Obama and French President Francois Hollande said Russia faced significant costs if it continues "provocative and destabilizing behavior."
Russian President Vladimir Putin ordered military forces to return to permanent bases after drills near Ukraine, the Kremlin said, although the Pentagon said it saw no indication of Russian troop movement away from the border.
A disruption to Ukraine's natural gas supplies seemed to be put off for now as Europe's Energy Commissioner said progress was being made in the gas price dispute between Russia and Ukraine, with a fresh round of negotiations scheduled for May 26.
Russia supplies around a third of Europe's gas demand, with about half of the European gas imports from Russia flowing through Ukraine. In recent weeks, Moscow has threatened to cut off or reduce Kiev's natural gas if the country does not pay outstanding debts.
(By Elizabeth Dilts; Additional reporting by Robert Gibbons in New York, Peg Mackey in London and Jacob Gronholt-Pedersen in Singapore; Editing by Jane Baird, David Gregorio and Paul Simao)