U.S. Consumer Price Index (CPI) rose 0.1 percent in May on seasonally adjusted basis, indicating the inflation remained subdued, the Labor Department said on Tuesday. The report said the energy prices rose 0.4 percent last month, with gasoline prices flat but increases in the electricity and natural gas prices accounting for the rise. Meanwhile, the food costs turned down by 0.1 percent in May. Excluding the volatile food and energy categories, the so-called \"core\" inflation index rose 0.2 percent in May. The consumer price index has risen 1.4 percent in the 12 months ending May, below the Federal Reserve\'s target inflation rate of 2 percent. Economists monitor core prices to get a sense of broader inflation trends, a key barometer for monetary policy decision of the central bank. A separate report released by the Labor Department last week showed the U.S. wholesale prices, a measure of price changes at factory gates, gained 0.5 percent last month on seasonally adjusted basis.