Oil prices have hit $100 per barrel for the first time in nearly four months.
The price of benchmark West Texas Intermediate crude rose as high as $100.79 in electronic trading on Wednesday.
Oil prices have been soaring for several weeks as the economy improves while tensions rise in countries that hold some of the world's major sources of crude.
Benchmark crude has surged 26 percent since the end of September. It crossed the $100 mark after the Labor Department reported that consumers paid less for gas, cars and computers. As inflation slows, it increases pressure on the Federal Reserve to do more to further stimulate the economy.
Fears of another U.S. recession had knocked oil prices from their 2011 peak at $113.93. But recent economic reports have shown that consumers are spending more, and manufacturing activity continues to grow.
Meanwhile, Iran, the world's fourth-largest oil exporter, is suspected of developing nuclear weapons, according to a United Nations report earlier this month. Its nuclear program could lead to international trade sanctions, and Israel has threatened military action.
Companies operating in Nigeria also say that oil production has been hurt by spills, sabotage and outright thefts. Nigeria is one of the top five oil exporters to the U.S.
Supplies of oil, gasoline and diesel also have been falling in the U.S.