WASHINGTON—The head of the agency that oversees the U.S. stockpile of nuclear weapons has resigned, the U.S. Energy Department's National Nuclear Security Administration said on Friday, without providing a reason.
Lisa Gordon-Hagerty resigned as administrator of the NNSA, a semi-autonomous branch of the department.
Gordon-Hagerty became the first woman to serve as administrator when she took up her post in early 2018.
NNSA oversees the development and maintenance of nuclear weapons, but not the delivery systems, which are managed by the Department of Defense.
DefenseNews was first to report Gordon-Hagerty's resignation.
The resignation drew criticism from Senator James Inhofe (R-Okla.), Republican chairman of the Armed Services Committee who praised Gordon-Hagerty and harshly criticized Secretary of Energy Dan Brouillette.
Inhofe alleged in a statement that "the Secretary of Energy effectively demanded her resignation."
Brouillette's office did not immediately respond to Reuters' request for comment.
Gordon-Hagerty had proposed a record budget of nearly $20 billion for fiscal year 2021 to help pay for modernization of the nuclear weapons stockpile, which is expected to cost more than $1.2 trillion over 30 years.
Brouillette had backed a budget of $17.5 billion proposed by the Office of Management and Budget, a White House office. President Donald Trump later sided with Gordon-Hagerty for a budget of nearly $20 billion.