Iran remained defiant after U.N. nuclear inspectors said they had failed in their latest mission to check activities at a site where the U.N. International Energy Agency said there is a facility to test explosives.
Iran's stance has sparked fears that Iran's confrontation with the West over its disputed nuclear program would escalate and affect oil flow from the Middle East.
Sanctions imposed by the United States against Tehran have already caused Asian buyers to cut purchases of Iranian oil while the European Union has moved to ban Iranian oil from July.
The bombardment of rebel sites by government forces in Syria and attacks on mostly Shi-ite targets across Iraq added to investor anxiety over the Middle East.
U.S. INVENTORIES, DEMAND ECONOMIC DATA
While U.S. inventories of distillates and gasoline showed modest declines last week, demand for refined oil products plunged to their lowest level in nearly 15 years, EIA data showed in the latest EIA report.
Total U.S. oil product demand on a four-week average basis fell last week by 6.7 percent year-on-year to 18.05 million barrels per day, the lowest level since April 1997.
Ahead of the U.S. summer driving season, motorists were cutting back on fuel usage due to high pump prices. (Additional reporting by Robert Gibbons and Matthew Robinson in New York, Zaida Espana and Simon Falush in London; Editing by Lisa Shumaker)