President Joe Biden was only told that US Defense Secretary Lloyd Austin was being treated for cancer on Tuesday, the White House has said.
Mr Austin, 70, was admitted to hospital on 1 January and then to the intensive care unit for complications following surgery in December.
He has faced criticism for not telling senior officials about it for days.
He has since apologised for not “ensuring the public was appropriately informed”.
The lag in notifying the White House raised potential national security concerns and issues of transparency within the Biden administration.
The defense secretary sits just below the president in the chain of command for the US military, and is one of the most important members of the president’s Cabinet.
The Pentagon confirmed Mr Austin remained hospitalised on Tuesday.
Read more at BBC.com