A senior official in the Treasury Department has told colleagues she is leaving the Trump administration, in the midst of intensifying trade negotiations, to seek a role in the private sector, according to sources familiar with her plans.

Julia Hahn, assistant secretary for public affairs, has said she is leaving soon, likely to start her own public affairs firm, two of the sources said.

Hahn was 25 when she started working at the White House during President Trump's first term, under then-chief strategist Stephen Bannon. She defended Mr. Trump as deputy White House communications director during his first impeachment trial. 

In his second term, Hahn, now 34, has worked on trade matters, sanctions and tax cuts. 

Treasury Secretary Scott Bessent told CBS News, "As she embarks on her next chapter, we wish her continued success and know she will carry forward the same passion and excellence that defined her time here."

White House deputy chief of staff Stephen Miller called Hahn an "invaluable asset" to the Treasury Department. "While her departure is a major loss to the administration, we know that she will continue to be an extraordinary ally on the outside," Miller told CBS News. 

Previously Hahn also worked for GOP Senator Bill Hagerty of Tennessee, as a producer at Laura Ingraham's radio show, and as a reporter for Breitbart during Bannon's time as an executive at the conservative website.