Pentagon Comptroller Elaine McCusker, who was reported to have questioned the suspension of U.S. military aid to Ukraine, a key element in the inquiry leading to President Donald Trump's impeachment, resigned on Tuesday, Defense Secretary Mark Esper said.
McCusker submitted her resignation as deputy undersecretary of defense (comptroller) effective June 26, Esper said in a statement, thanking her for her public service and contributions to the Pentagon's budgeting and audit processes, Reuters said.
Trump last year nominated McCusker to be promoted to undersecretary of defense (comptroller), but withdrew the nomination in March, after the White House ousted several other officials who had testified at his impeachment inquiry.
Trump was impeached by the Democratic-led House of Representatives in December. Democrats said Trump held back US$391 million in security aid to Ukraine and a White House meeting for President Volodymyr Zelensky as leverage to force Kyiv into interfering in the 2020 U.S. presidential election by smearing Democratic candidate Joe Biden.
Trump, who branded the impeachment effort a witch hunt, was acquitted in February after a trial in the U.S. Senate, where his fellow Republicans have a majority.
Senator Jack Reed, the top Democrat on the U.S. Senate Armed Services Committee, said in March that witness testimony and leaked emails between McCusker and the Office of Management and Budget showed that she had repeatedly raised concerns about Trump's hold on Ukraine security assistance and "sought to ensure that the Administration was in compliance with the law."