The U.S. is "at some risk" of seeing an inverted yield curve later this year or early in 2019, which should give the Federal Reserve Board pause as it seeks to hike interest rates further, Federal Reserve Bank of St. Louis President and CEO James Bullard said May 14.

Bullard said the Fed's rate increases have helped flatten the yield curve. Inversion of the yield curve has historically signaled an upcoming recession. As of May 11, the spread between 10-year Treasury yields and 2-year yields was about 43 basis points, significantly flatter than the roughly 100-basis-point spread in 2017.

The Fed does "not need to be so aggressive" and potentially invert the yield curve, he said, reiterating his view that additional rate hikes are unnecessary right now.

"I think we've got the right level of a policy rate today, and so I think we could just stay where we are," he told reporters at a New York City event.

Bullard is not a voter this year on the Federal Open Market Committee, which has penciled in two more rate increases this year.