The Federal Reserve delivered an unexpected blow to hopes for lower borrowing costs in the future, projecting higher inflation and higher interest rates in updated forecasts released Wednesday. While policymakers left their benchmark rate unchanged and signaled that they may cut in the second half of this year, forecasts of officials showed they expect fewer cuts next year and the year after that. The central bank held the federal funds target at 4.25 to 4.50 percent, its level since the December rate cut. But the accompanying economic projections revealed rising concern that inflation is not receding fast enough—and that rates...