The US Labor Department's consumer price index increased 0.2 percent in April, less than economists' expectations, as rising costs for gasoline and rental accommodation were tempered by a moderation in healthcare prices.
Core CPI, which excludes food and energy components, edged up 0.1 percent in April, slower than the previous two months, and did little to alter traders' expectations of a June rate hike.
A higher inflation number could have increased fears of more aggressive interest rate hikes by the US Federal Reserve.