Import prices rose in February on sharply higher petroleum costs, but there were little signs of underlying imported inflation pressures as food prices posted their largest decline in three years.

Overall import prices rose 0.4 percent, the Labor Department said on Wednesday. January's data was revised to show a flat reading instead of the previously reported 0.3 percent increase.

Economists polled by Reuters had expected prices to rise 0.6 percent last month. The dollar fell 1.7 percent on a trade-weighted basis in February and likely contributed to the rise in the cost of imports.

The Federal Reserve on Tuesday said the recent steep run-up in oil and gasoline prices would push inflation up, but only temporarily. Long-term inflation expectations remained stable, the central bank said.

Stripping out petroleum, import prices dropped 0.2 percent, pointing to benign inflation pressures - after being flat in January.

Data on Thursday is expected to show that energy pushed producer prices up 0.5 percent last month, according to a Reuters survey, after edging up 0.1 percent in January.

Outside food and energy, wholesale prices are expected to have moderated, with a gain of 0.2 percent forecast after a 0.4 percent increase in January.

Last month, imported petroleum prices increased 1.8 percent after gaining 0.3 percent in January. Imported food prices fell 3.0 percent in February - the biggest decline since February 2009 - reversing January's 2.3 percent increase.

Elsewhere, imported capital goods prices edged down 0.1 percent after advancing 0.4 percent in January. Imported motor vehicle prices were flat after rising 0.4 percent in January.

The Labor Department report also showed export prices rose 0.4 percent last month, above analysts' expectations for a 0.2 percent gain. Export prices increased 0.2 percent in January.