Crude oil futures prices were trading lower Thursday after a report the U.K expects the U.S. to move soon to open its emergency oil reserves in the face of rising prices.

Reuters quoted U.K. sources saying they expected the request soon and said the U.K. would cooperate with the move.

The U.S. was the lynchpin of a move by the International Energy Agency in June 2011 to release 60 million barrels of crude oil from its Strategic Petroleum Reserve amid concerns over a supply shortage caused by the Libyan civil war. The U.S. provided half of the emergency oil released.

Rising prices amid worries about a potential cutoff in Iranian oil supplies, as western sanctions tighten, has stirred market chatter than a similar release may be forthcoming. North Sea Brent crude oil prices have recently traded to near their highest levels since 2008 and gasoline prices in the U.S. have climbed and are widely expected to top $4 a gallon nationwide for the first time since summer 2008.

Nymex April light, sweet crude oil was trading about 50 cents higher before the headline and was recently down $1 at $104.43 a barrel. It moved in a range of $103.78 to $106.18 a barrel.

April Brent crude was $123.00 a barrel, down $1.97 a barrel, after trading in a range of $120.97 to $125.35 a barrel.

-By David Bird, Dow Jones Newswires; 212-416-2141; david.bird@dowjones.com