Related: OPEC keeps output at 28mln barrels

    NEW YORK, Jan. 31 (Xinhuanet) -- World crude oil prices fell below $68 a barrel Tuesday after OPEC decided to keep the maximum oil output.

    New York's main contract, light sweet crude for delivery in March, dropped 43 cents to settle at 67.92 dollars a barrel.

    Heating oil futures fell nearly 3.19 cents to settle at 1.8019 dollars a gallon, while gasoline futures declined by 4.91 cents to settle at 1.7258 dollars a gallon. Nymex natural gas fell 7.3 cents to 9.316 dollars per 1,000 cubic feet.

    The 139th Meeting of the OPEC Conference sealed a deal Tuesday to keep the oil output ceiling of the OPEC at a maximum 28 million barrels per day, aiming to tackle crying price and increasing demand.

    The U.S., Britain, France, China and Russia agreed Tuesday to back the referral of Iran's nuclear program to the United Nations Security Council at a Feb. 2 meeting of the International Atomic Energy Agency.

    The IAEA is demanding that Iran declare all of its nuclear activities and suspend enrichment-related programs. On Jan. 10, Iran announced to relaunch nuclear research, igniting tension between the West and this second biggest oil producer within the OPEC. Enditem