Jerome Powell

As the Federal Reserve considers whether to increase interest rates for the first time in nearly a decade, policymakers should look for "a little more proof than usual" that labor markets are tightening, said Jerome Powell, a central bank governor, in remarks prepared for a Wednesday speech at the Council on Foreign Relations in New York City.

"Despite slowing in March, job creation has been particularly strong over the past two years," he said. "[But] the unemployment rate probably understates the amount of slack still remaining in the labor market."