US inflation continued to surge in May as prices for used cars and energy picked up. Consumer prices jumped five per cent in the 12 months to the end of May, up from 4.2% per cent the month before. The new figures from the US Labor Department mark the biggest year-on-year increase since August 2008. It comes amid fears that rising prices could prompt the US central bank, the Federal Reserve, to push up interest rates. However, some analysts have said, inflation could be rising because of temporary factors such as supply bottlenecks.