The Labor Department says its consumer price index rose 0.4 per cent in May, the biggest one-month jump since a 0.6 per cent increase in February 2013.
Over the past 12 months, consumer prices are up 2.1 per cent. While that was the biggest 12-month price change since October 2012, it still left prices rising at a modest pace near the Federal Reserve's 2 per cent target.
Excluding volatile food and energy, core inflation was up 0.3 per cent in May, the biggest one-month gain since August 2011. Over the past 12 months, core prices are up 2 per cent.