Former US Defence Secretary James Mattis has denounced President Donald Trump, accusing him of stoking division and abusing his authority.
In rare public comments, Mr Mattis said the president had sought to “divide” the American people and had failed to provide “mature leadership”.
He said he was “angry and appalled” by Mr Trump’s handling of recent unrest.
In response, the president described Mr Mattis as an “overrated general” and said he was glad he had left the post.
Mr Mattis resigned in 2018 after Mr Trump decided to withdraw US troops from Syria.
He has remained mostly silent since then, until his stinging rebuke of the Trump administration was published in The Atlantic magazine on Wednesday.
In response to the fresh criticism, Mr Trump posted a series of tweets in which he claimed to have fired Mr Mattis.
“I didn’t like his “leadership” style or much else about him, and many others agree,” he wrote. “Glad he is gone!”