WASHINGTON (REUTERS) - President Barack Obama on Wednesday named economist Nathan Sheets, who has worked at Citigroup and the Federal Reserve, as the Treasury Department's top international official, the White House said.

The Treasury post of under secretary for international affairs was previously occupied by Lael Brainard, who stepped down last year and who Obama nominated to serve on the Fed's board of governors.

Sheets has been the global head of international economics at Citi in New York since 2011. Prior to joining Citi, one of the world's largest banking conglomerates, Sheets spent much of his career as an economist at the Fed.

Obama also named Mark Sobel as US executive director at the International Monetary Fund.