John Williams, president and chief executive officer of the Federal Reserve Bank of San Francisco, speaks at an event in Los Angeles, California on Sept. 28, 2015.

New York Federal Reserve President John Williams said in a speech Wednesday that sluggish inflation is one of the central bank's most pressing issues and promised to use monetary policy to sustain economic growth in the U.S.

"Low inflation is indeed the problem of this era. The current outlook of moderate growth, low unemployment, but stubbornly low inflation is a reflection of the broader economic picture," Williams said. "I am carefully monitoring this nuanced picture and remain vigilant to act as appropriate to support continuing growth, a strong labor market, and a sustained return to 2 percent inflation."

The influential Fed policymaker spoke just two weeks before the Federal Open Market Committee is expected to cut its benchmark interest rate during the Sept. 17-18 meeting.

"Germany, the UK, and China are all experiencing slowdowns, and the euro area is of particular concern," Williams said. "On our own shores, concerns around trade policy with China are adding to an uncertain picture. My contacts in the business community have said this is making them more cautious about investment. The effects of this angst are already showing up in the investment numbers."