The head of the Department of Energy division responsible for overseeing and maintaining the U.S. nuclear weapons arsenal is stepping down, according to a statement issued on Saturday.
"The ability to serve our nation is a privilege and I have been blessed to be able to do so for many years," wrote Tom D'Agostino, head of the National Nuclear Security Administration (NNSA).
"It has been truly an honor and privilege to serve with you and to serve the country in the wide variety of roles and opportunities I have been presented," D'Agostino wrote in his farewell to the division.
His last day at NNSA will be Jan. 18, the final day of the Obama administration's first term in office.
Neile Miller, currently the principal deputy administrator at NNSA, will serve as acting administrator until the White House chooses a nominee to fill the position.
"Tom D’Agostino has proven himself to be a talented leader, a trusted adviser, and a true confidant," Energy Secretary David Chu said in a statement issued the same day.
"Under his watch, we have eliminated or secured hundreds of nuclear weapons worth of nuclear materials," Chu added. "We have reduced the number of deployed warheads to the lowest level since the 1950s . . . while successfully maintaining the safety, security, and effectiveness of a shrinking stockpile."
D'Agostino is the latest in a number of top U.S. national security officials to leave the White House as the administration enters its second term.
The White House filled one of those gaps on Friday, naming Sen. John KerryJohn KerryOvernight Energy & Environment — Presented by the League of Conservation Voters — EPA finalizing rule cutting HFCs Overnight Energy & Environment — Presented by the League of Conservation Voters — Senate Finance chair backs budget action on fossil fuel subsidies Kerry: 'We can't get where we need to go' in climate fight if China isn't joining in MORE (D-Mass.) to replace outgoing Secretary of State Hillary ClintonHillary Diane Rodham ClintonDemocrats worry negative images are defining White House Heller won't say if Biden won election Whitmer trailing GOP challenger by 6 points in Michigan governor race: poll MORE.
However, the Obama administration has yet to officially name its top picks for the Defense Department and CIA. Former Nebraska Republican Sen. Chuck HagelCharles (Chuck) Timothy HagelAfghan interpreter who helped rescue Biden: 'If they find me, they will kill me' Afghan interpreter who helped extract Biden, other senators in 2008 asks president to save him Democrats defend Afghan withdrawal amid Taliban advance MORE has been tagged as the administration's presumptive pick for the Pentagon.