The president of the Federal Reserve Bank of San Francisco said he "would not rule out" the prospect of more than three rate increases in 2017.

San Francisco Fed President and CEO John Williams, who does not currently vote in the policy-setting Federal Open Market Committee, said in a speech March 29 that the Fed's dual goals of full employment and 2% inflation are "close at hand."

However, he noted that the Fed cannot control supply-side factors that are now the "main impediment to growth going forward," with labor force participation and productivity expected to grow at a slower pace than in previous recoveries.

"Unshackling the economy from these supply-side restraints is instead the purview of things like federal fiscal policy, state and local legislative actions, philanthropy, business investment, public-private partnerships, etc.," he said, according to prepared remarks.