The price of oil fell 2 percent to its lowest level in a month after OPEC stuck to its current production target despite ample supplies of crude.
U.S. crude oil futures fell $1.64 to close at $91.97 Friday in New York.
Brent crude, a benchmark for pricing oil used by many U.S. refineries to make gasoline, fell $1.80 to close at $100.39 in London.
Secretary General of OPEC Abdalla Salem El-Badri of Libya arrives for a news conference after a meeting of the Organization of the Petroleum Exporting Countries, OPEC, at their headquarters in Vienna, Austria, Friday. OPEC oil ministers have decided to keep the organization's output target at 30 million barrels a day.
The average price of a gallon of gasoline in the U.S. slipped less than a penny to $3.61 per gallon. Prices rose 10 cents during May, or 3 percent, mainly due to refinery problems in the Midwest. Still, May prices averaged less this year than they did in either of the last two years, according to AAA.
The automobile association expects the average price of gasoline to continue to slide, and fall below $3.50 a gallon in June.
The Organization of Petroleum Exporting Countries said Friday it would keep its official output target of 30 million barrels a day - one third of the world's daily consumption - even though world oil supplies are abundant and some regions, including the majority of the European Union, are in recession.
At the end of a meeting at its headquarters in Vienna, OPEC said that steady prices in recent months showed that the market was "adequately supplied" and that no action was needed.
Oil prices have traded in a range between $88 and $98 per barrel through the first five months of the year. The average for the year is $94.01 per barrel, just 13 cents less than the 2012 average.
OPEC has been producing more oil than members agreed to, helping to boost global supplies. Analysts say that could lead to lower prices in the coming months.
"In view of the current oversupply and in the absence of any positive surprises from OPEC, oil prices are likely to remain under pressure," said analysts at Commerzbank in Frankfurt.