U.S. inflation in May accelerated to the fastest pace in more than six years, the latest sign of growing price pressures in the U.S. economy.

The consumer price index in May rose 0.2 percent from the previous month and 2.8 percent from a year earlier, marking the strongest annual growth since February 2012, the Labor Department reported on Tuesday.

One driver of higher prices last month was the index for gasoline, which increased 1.7 percent and led to a 0.9-percent rise in the energy index, the department said.

Excluding food and energy, the so-called core consumer price index was up 0.2 percent from the prior month and 2.2 percent from a year ago.

Tuesday's report came before Federal Reserve officials start a two-day policy meeting. Economists and market participants are widely expecting that the Fed will announce on Wednesday to raise interest rates again to keep U.S. economy from overheating.

The Fed has signaled that it will raise interest rates "soon" if economic outlook is in line with expectation of Fed officials.

"Most participants judged that if incoming information broadly confirmed their current economic outlook, it would likely soon be appropriate for the (Federal Open Market) Committee to take another step in removing policy accommodation," the Fed said in the minutes for its latest policy meeting released last month.