US Attorney for the Southern District Berman has released the following statement:
“I learned in a press release from the Attorney General tonight that I was ‘stepping down’ as United States Attorney. I have not resigned, and have no intention of resigning, my position"
It is unclear what Berman can do keep his position, but it appears that he is intent on making sure that the work of his office continues.
Edited to note, since Berman refused to step down, Barr asked Trump to fire Berman, which Trump did.
Edited again to add that Berman has stepped down since Barr has agreed to appoint Deputy US Attorney Audrey Strauss as acting US Attorney.