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.
Higher gasoline prices are weighing on the economy which is already struggling with high unemployment and a moribund housing sector following the 2007-2009 recession.
A separate report showed applications for U.S. home mortgages fell last week despite a drop in the average interest rate for 30-year mortgages.
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.
Imported petroleum prices increased 4.3 percent, the biggest gain since April 2011.
Markets showed little reaction to the data. Stock futures were higher, pointing to a firmer open after five days of losses. Treasury debt prices were lower.
Higher prices for energy have fueled inflation in recent months but a still-weak jobs market has made it harder for businesses to pass those costs on to consumers.
The National Federation of Independent Business said on Tuesday that rising prices also are weighing on sentiment among small businesses owners. Last month, 9 percent of firms surveyed by the NFIB said inflation was their top business problem.
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.
The Labor Department report showed that, stripping out petroleum, import prices increased 0.3 percent last month after falling 0.1 percent in February.
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.
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.
(Additional reporting by Leah Schnurr in New York; Editing by Andrea Ricci)