WASHINGTON—President Trump plans to nominate economists Judy Shelton and Christopher Waller to fill two board vacancies at the Federal Reserve, after months of pressing the central bank to lower interest rates.

Mr. Trump announced his intentions in a series of tweets on Tuesday, noting that Ms. Shelton currently serves as U.S. executive director at the European Bank for Reconstruction and Development, while Mr. Waller is director of research at the Federal Reserve Bank of St. Louis.

Mr. Trump recently dropped plans to nominate two other picks, conservative pundit Stephen Moore and onetime Republican presidential contender Herman Cain. Both of them withdrew from consideration after Republican senators expressed reservations about their personal backgrounds, policy views and qualifications for the job.

Ms. Shelton was confirmed by the Senate for her current EBRD role by a voice vote in 2018.

Mr. Waller, a trained economist, holds a Ph.D. from Washington State University and headed the University of Notre Dame’s economics department before joining the St. Louis Fed in 2009.