Oil prices are climbing after Iran says it will cut off some crude exports to Europe in retaliation for a planned embargo later this year.
Benchmark US crude rose by $US1.08 ($A1.01) to $101.82 per barrel in New York. Brent crude, which is used to price foreign oil that's imported by refineries, rose by $1.53 to $118.88 per barrel in London.
Stopping Iranian shipments means European refineries will have to find new sources of oil sooner than expected. The European Union (EU), which buys about 18 per cent of Iran's total crude exports, had planned to embargo Iranian oil this summer to pressure the country to abandon its nuclear program.
Western nations, including the US, fear that Iran is building a nuclear weapon. Iran denies the claim.
The EU embargo, announced last month, was planned to begin after July to give refineries time to switch their supply contracts to other countries. Iran's move could force them to switch those contracts faster, increasing demand in the short term.
Iran's state media reported early on Wednesday that the country was taking steps to cut off oil exports to six European countries. The reports said that Iran halted exports to France and the Netherlands, and has given an ultimatum to Italy, Spain, Portugal and Greece to either sign long-term contracts with Iran or be cut off as well.
Independent oil analyst Jim Ritterbusch said the announcement was mostly bluster.
"They're trying to keep the market hyped up," Ritterbusch said. "Iran knows that by cutting off exports, it only hurts themselves. It reduces their revenue stream."
Iran gets about half of its revenue from oil exports. Experts say Iran will probably sell oil to China and India to make up for the loss of European sales. That oil may be sold at a discount, however, since much of the international community is turning its back on Iranian oil.
Meanwhile, investors were encouraged by strong gross domestic product reports from Germany and France that indicates Europe's economy may not have contracted as much as feared last year.
US oil supplies fell unexpectedly last week, though the government says demand remains weak. The Energy Information Administration said that four-week average petroleum demand dropped by 4.6 per cent while petrol demand fell by 6.4 per cent, when compared with the same period last year.
Retail petrol prices rose by less than a penny to a national average of $3.52 per gallon (3.8 litres), according to AAA, Wright Express and Oil Price Information Service. A gallon of regular is 13 cents more than it was a month ago and 39 cents higher than at the same time last year.
In other energy trading, heating oil rose 3 cents to $3.20 per gallon and petrol futures rose by about a penny to $3 per gallon. Natural gas futures fell by 11 cents, or 4.3 per cent, to $2.43 per 1,000 cubic feet.