U.S. import prices rose in February as petroleum surged, a government report showed Wednesday, but underlying imported inflation pressures remain muted.

Overall import prices were up 0.4 percent, the Labor Department said, marking only the second time import prices have recorded a monthly advance greater than 0.1 percent since the index rose 2.6 percent in April 2011. Economists polled by Thomson Reuters had called for prices to rise 0.6 percent last month, with the expectation that not both petroleum prices and food prices would rise significantly and contribute to the topline figure.

The restraining effects of the U.S. dollar appreciation last year faded as the dollar has weakened during the first two months of 2012.

Imported petroleum costs rose 1.8 percent in February after advancing 0.3 percent in January, while imported food prices dipped unexpectedly by 3.0 percent in February, following a surge of 2.3 percent in the prior month.

Excluding oil and food, import prices fell 0.2 percent after a flat January.

The recent increase in oil and gasoline prices will push up inflation temporarily, according to Tuesday's Federal Open Market Committee meeting statement. However, long-term inflation expectations have remained stable.

Fed officials said they expect inflation to settle at levels at or below those consistent with its price stability mandate.

Elsewhere, imported capital goods prices declined 0.1 percent after advancing 0.4 percent in January. Imported motor vehicle prices remained unchanged, following a 0.4 percent rise in the prior month.

The Labor Department report also showed export prices advanced a more-than-expected 0.4 percent in February, after rising 0.2 percent in January. Nonagricultural industrial supplies and materials prices contributed to the increase.

Most economists had expected the increase in export prices to match its pace in January and post a 0.2 percent gain.

The 0.4 percent advance in export prices in February marked the largest monthly increase since a 0.5 percent rise in September.Despite recording the largest monthly increase in five months, overall export prices rose only 1.5 percent over the past 12 months, the smallest year-over-year advance since a 0.4 percent rise for the November 2008-09 period.