Sudden departure of Daniel Driscoll comes after Pentagon chief removed senior officers and blocked promotions, prompting warnings of a leadership crisis

A senior Senate Democrat accused Pentagon secretary Pete Hegseth of having “hollowed out” the army’s senior ranks after its top civilian leader resigned after months of internal clashes with Hegseth.

No official reason was given for army secretary Daniel Driscoll’s departure after 18 months on the job, while thousands of US soldiers are deployed in the Middle East. In a statement on Monday night, White House spokesperson Anna Kelly said Driscoll had been “highly effective in advancing President Trump’s agenda”, citing his work on “readiness and lethality” and his role in Russia-Ukraine negotiations.