Oil prices edged up Wednesday after a government report showed an unexpected decline in weekly U.S. crude oil inventories, suggesting that the recent frigid weather is eating into supplies.

The Department of Energy said Wednesday that crude oil inventories fell by 400,000 barrels last week to 324.5 million barrels. Analysts expected an average build of 950,000 barrels, according to a Dow Jones Newswires survey of energy analysts.

"This report is solid confirmation of solid heating demand," said Tim Evans, energy analyst at Citigroup Global Markets.

Crude supplies remain at the upper end of the average range for this time of year, however.

Light, sweet crude for March delivery inched up 7 cents to $58.95 a barrel in late morning trading on the New York Mercantile Exchange.

Brent crude was unchanged at $58.42 Wednesday on London's ICE commodities exchange.

The government also reported that distillate fuel inventories — which includes heating oil and diesel fuel — fell by 3.7 million barrels, more than analysts' expectations of a 2.9-million-barrel drawdown.

Meanwhile, motor gasoline inventories rose by 2.6 million barrels, surprising analysts who expected an average gain of 1.35 million barrels. Both distillate fuels and gasoline stocks remain at the upper end of average for this time of year.

Heating oil futures rose by half a penny to $1.6960 a gallon, while gasoline futures rose by less than a cent to $1.5739 a gallon.

Recent bitter winter weather in the U.S. Northeast — which makes up 80 percent of the nation's heating oil demand — has helped to buoy crude oil and heating oil prices this week.

The National Oceanic and Atmospheric Administration continues to forecast below-normal temperatures across the U.S. Northeast until at least Feb. 19. The low temperatures have helped lift prices 19 percent since Jan. 18, when crude touched a 20-month low of $49.90.

Traders have yet to send prices above $60 a barrel, a level not seen since the first trading day of the year. Continued cold weather may not be enough to boost prices over that "psychological barrier," especially this late in the winter season, according to Ray Mazzeo, vice president at Energy Merchant LLC.

Instead, Mazzeo expects increasing tensions between Iran and the U.S. to be the main driver in boosting prices.

"I think the anticipation of the expiring of the Iran sanctions has brought us to this level so far," Mazzeo said. "If we get a hard line from Iran refusing to stop uranium enrichment, then we could see $60 a barrel."

In other Nymex trading, natural gas prices advanced more than 14 cents to $7.758 per 1,000 cubic feet.