Washington | US Federal Reserve policymakers expect to cut interest rates just once this calendar year, two fewer than they saw in March, as they forecast inflation will take longer to slow to their 2 per cent goal than previously thought.

The Fed kept the federal funds rate unchanged at between 5.25 per cent and 5.5 per cent on Wednesday (Thursday AEST) in a widely expected move, and said no rate cuts would be made until it was clearer inflation was on a path towards its target.