Consumer prices in the United States dropped 0.1 percent in October as energy costs declined, the Labor Department reported Wednesday.

In the past 12 months, the Consumer Price Index (CPI), which tracks inflation at the retail level, rose by 3.5 percent before seasonal adjustment.

The report said that energy prices decreased 2.0 percent in October after rising 2.0 percent a month earlier. Gasoline prices dropped 3.1 percent following a 2.9 percent increase in the previous month.

Meanwhile, food costs rose 0.1 percent last month after posting a 0.6 percent gain in September.

Excluding the volatile food and energy categories, the so-called "core" index rose 0.1 percent in October, the smallest increase since March. The 12-month change for the core index rose 2.1 percent last month.

Economists monitor core prices to get a sense of broader inflation trends, a key barometer for monetary policy decision.

VietNamNet/Xinhuanet