WASHINGTON (AP) — President Donald Trump says on Twitter he will nominate economists Christopher Waller and Judy Shelton to fill two vacancies on the Federal Reserve Board of Governors.

Waller is currently the executive vice president and director of research at the Federal Reserve Bank of St. Louis, where he has worked since June 2009. Shelton is the U.S. executive director for the European Bank of Reconstruction and Development.

Trump’s choices come at a time when he has harshly criticized the Fed under Chair Jerome Powell for choosing not to cut interest rates.