The Atlantic on Wednesday released the entire Signal chat among senior national security officials, showing that Defence Secretary Pete Hegseth provided the exact timings of warplane launches and when bombs would drop – before the men and women flying those attacks against Yemen’s Houthis this month on behalf of the United States were airborne.

The disclosure follows two intense days during which leaders of US President Donald Trump’s intelligence and defence agencies have struggled to explain how details that current and former American officials have said would have been classified wound up on an unclassified Signal chat that included Atlantic editor-in-chief Jeffrey Goldberg,

White House press secretary Karoline Leavitt has said no classified information was posted to the Signal chat.

The chat was also notable for who it excluded: the only military attendee of the principals committee, the chairman of the Joint Chiefs of Staff.

Admiral Christopher Grady is currently serving in that position in an acting capacity because Trump fired former chairman General C.Q. Brown Jnr in February.

National security adviser Mike Waltz was authorised to decide whether to include the Joint Chiefs chairman in the principals committee discussion, “based on the policy relevance of attendees to the issues being considered, the need for secrecy on sensitive matters, staffing needs, and other considerations”, the White House said in a January 20 memo.