Crude oil and natural gas prices declined sharply Tuesday on shrunk demand due to mild weather in the United States.

Light sweet crude for February delivery declined 1.31 dollars, or 2.09 percent, to 61.10 dollars a barrel on the New York Mercantile Exchange (NYME).

The price of Brent quality North Sea oil for delivery in February ended at 61.1 dollars a barrel, losing 1.32 dollars from Friday.

Natural gas prices on the NYWE dropped 52.20 cents, or 7.87 percent, to 6.113 dollars per 1,000 cubic feet.

The energy markets were under the pressure of the unusual weather despite Iran may use oil as a weapon against UN sanctions, said analysts.

Temperatures in the U.S. Northeast had averaged 5-8 degrees ( Centigrade) above normal over the long Christmas holiday weekend.

The latest weather forecasts indicated that in the coming two weeks the U.S. Northeast, the major heating oil and gas consumer in the world, would experience warmer-than-normal temperatures.

Oil prices rose a little earlier in the day as Iranian Oil Minister Kazem Vaziri Hamaneh said Iran reserves the right to resort to oil as a weapon.

Iran, the world's fourth-largest crude producer, has condemned the UN resolution as illegal and vowed to speed up enrichment work.

However, traders would probably disregard the latest developments unless they saw evidence of supply disruption, said analysts.