WASHINGTON (AFP) – US consumer prices rose for the 11th straight month in May but at a slower pace amid easing energy prices, official data showed Wednesday.

The consumer price index climbed a seasonally adjusted 0.2 percent, the Labor Department said. Year-on-year, prices were up 3.6 percent, chewing away at consumers' earnings.

Core inflation -- a key measure that excludes volatile fuel and food prices, and is watched by the Federal Reserve to set interest rates -- jumped by 0.3 percent in May from the previous month. That was the sharpest increase since July 2008.

But the core inflation figure, despite May's surge, remained 1.5 percent year on year, still well within the Federal Reserve's inflation comfort zone.

The month's headline CPI figure was half the 0.4 percent increase in April but double the average analyst forecast of a 0.1 percent gain.

Overall energy prices led the slowdown, with gasoline prices falling for the first time since last June, by 2.0 percent.

But household energy prices rose, as did food prices, which surged 0.4 percent for the second consecutive month.

The pullback in energy costs for US consumers "is a positive development that should help limit some of the fallout from the May report, especially since the spike in energy prices has been widely regarded as a major catalyst contributing to the soft patch of data of late," said Patrick O'Hare at Briefing.com.

The latest numbers on a 12-month basis showed building momentum in consumer prices. Broad inflation was only 1.1 percent as recently as November, the department noted.