The Federal Reserve dropped an assurance it will be "patient" in raising interest rates, ending an era in its communications policy and opening the door for higher borrowing costs as early as June.

"An increase in the target range for the federal funds rate remains unlikely at the April" meeting, the Federal Open Market Committee said in a statement Wednesday in Washington. The panel said it will be appropriate to tighten "when it has seen further improvement in the labor market and is reasonably confident that inflation will move back to its 2 percent objective over the medium term."

Chair Janet Yellen is preparing for an exit from the most aggressive easing in the Fed's 100-year history as the job market overcomes the damage wrought by the deepest recession since the 1930s. At the same time, inflation and wage growth that remain too low are giving her reasons for caution.