 The U.S. central bank has announced its biggest interest rate increase in more than two decades as it toughens its fight against fast rising prices. The Federal Reserve said it was lifting its benchmark interest rate by half a percentage point to a range of 0.75% to 1% after a smaller rise in March, where its U.S. inflation at a 40-year high further hikes are expected. The push marks the latest effort to contain spike in costs being felt by households around the world.