NEW YORK, April 11 (Xinhua) -- World crude oil prices hit a seven-month high of 69 dollars Tuesday amid concerns that Iran's nuclear standoff and violence in Nigeria could undermine supplies.

    New York's main contract, light sweet crude for delivery in May, added 24 cents to close at 68.98 dollars a barrel, its highest closing price since Sept. 1, after touching an intra-day high of 69.45 dollars.

    On London's ICE Futures exchange, the price of Brent North Sea crude for May delivery climbed 62 cents to 69.37 dollars a barrel, its record high since 1988.

    On the New York Mercantile Exchange, the heating oil rose 1.01 cent to 1.9555 dollars a gallon as gasoline futures was up 4.52 cents to 2.0544 dollars per gallon. Natural gas futures was up 2.6 cents to 6.908 dollars per 1,000 cubic feet.

    Iran's Atomic Energy Organization confirmed on Tuesday that Iran had enriched uranium to a level used in nuclear power plants. Iranian President Mahmoud Ahmadinejad declared earlier that his country was poised to enter the world's "nuclear club".

    Traders are still concerned about Iran's nuclear standoff with the international community and violence in Nigeria that has forced the shutdown of more than half a million barrels a day of supply.

    Iran is OPEC's number-two producer behind Saudi Arabia, making four million bpd of oil and exporting 2.4 million bpd.

    Nigeria is Africa's leading oil producer and the fifth-biggest source of U.S. oil imports. Enditem