U.S. import prices rose in March by the most in nearly a year on sharply higher petroleum costs, but prices outside food and energy climbed more modestly.

Overall import prices rose 1.3 percent, the Labor Department said on Wednesday. That was the biggest gain since April 2011.

Economists polled by Reuters had expected import prices to rise 0.8 percent last month. February's data was revised to show a 0.1 percent decline instead of the previously reported 0.4 percent increase.

Stripping out petroleum, import prices increased 0.3 percent after falling 0.1 percent in February.

Higher costs for energy have fueled inflation in recent months but a still-weak jobs market has made it harder for businesses to raise other prices.

A report last week showing slower job growth in March has fueled speculation the U.S. Federal Reserve could ease monetary policy further. Most major Wall Street firms expect the Fed to launch a third round of bond buying, a Reuters poll found on Monday.

Data on Thursday is expected to show tame price pressures at a wholesale level, with producer prices seen rising 0.2 percent in March when stripping out food and energy.

But Wednesday's report underscores the size of the price shock that is stinging Americans when they refuel their cars.

Last month, imported petroleum prices increased 4.3 percent, the biggest gain since April 2011.

Elsewhere, imported capital goods prices edged 0.2 percent higher after being flat in February. Imported motor vehicle prices climbed 0.3 percent after being unchanged in February.

The Labor Department report also showed export prices rose 0.8 percent last month, above analysts' expectations for a 0.4 percent gain. Export prices increased 0.4 percent in February.