Oil prices fell Monday as Europe's ongoing debt crisis fueled concerns about future energy demand.
Benchmark crude finished down 42 cents at $86.38 per barrel in New York, while Brent crude, used to price international varieties of oil, fell $2.07 to end at $110.16 a barrel in London.
Oil has tumbled about 24 percent since May on fears of a slowdown in the global economy. Investors focused on weak gasoline demand in the U.S. and budget problems in Greece.
Prices had started to rise last week as European leaders appeared to be near a turning point. In Monday German finance chief Wolfgang Schaeuble dampened expectations that they'd hammer out a comprehensive solution at an upcoming summit.
Meanwhile, U.S. factories produced more goods in September for the third month. The 0.4 percent increase in factory output was taken as a sign that the economy is still growing, albeit slowly.
Gasoline pump prices rose a half penny to a national average of $3.462 per gallon, according to AAA, Wright Express and the Oil Price Information Service. A gallon of regular has fallen about 52 cents from its peak near $4 per gallon on May 5, but it's still nearly 63 cents higher than the same time last year.
In other energy trading, heating oil lost 4.2 cents to finish at $3.0136 per gallon and gasoline futures lost 8.18 cents to end at $2.7429 per gallon. Natural gas lost 1.5 cents to finish the day at $3.688 per 1,000 cubic feet.