U.S. consumer prices rose a moderate amount in May, driven up by rising energy costs and the biggest increase in shelter costs in more than nine years.

The Labor Department says consumer prices increased 0.2 percent last month following a 0.4 percent April increase. Energy prices rose for a third straight month, but food costs fell.

Core inflation, which excludes volatile food and energy, was also up 0.2 percent in May.

Over the past 12 months, overall inflation has risen a modest 1 percent, reflecting in part the fact that energy prices are down 10.1 percent over that time period. Core inflation is up 2.2 percent over the past 12 months.

The Federal Reserve says it is still concerned that inflation is running at too low a rate.