Related: US commercial crude oil stocks rise to 8-year high
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    NEW YORK, May 11 (Xinhua) -- World crude oil prices surged above 73 dollars on Thursday amid worries over Nigeria and Iran.

    New York's main contract, light sweet crude for delivery in June, added 1.19 dollars to close at 73.32 dollars a barrel.

    On London's ICE Futures exchange, the price of Brent North Sea crude for June delivery was up 99 cents to settle at 73.43 dollars a barrel.

    Three foreign workers were kidnapped on Thursday in Port Harcourt, Nigeria., after the murder of an American oil industry executive in the same city.

    About one-fourth of Nigeria's daily output is still shut after a series of militant attacks. Nigeria is Africa's leading oil producer and the fifth-biggest source of U.S. oil imports.

    U.S. State Department spokesman Sean McCormack said on Wednesday that U.S. expects to see actions by the United Nations Security Council in the settlement of Iran's nuclear crisis after a couple of weeks.

    Inventories of U.S. commercial crude oil and gasoline climbed last week, the Energy Department reported Wednesday in its weekly nationwide survey.

    Data showed that the nation's commercial crude oil inventories climbed by 300,000 barrels to 34 7 million barrels, or 5 percent above year-ago levels.

    Gasoline stockpiles rose by 2.4 million barrels to 205.1 million barrels, or 3.8 percent below year-ago levels. Enditem