President Joe Biden has thrown his support behind the top US military officer, Mark Milley, a day after a new book says he went around civilian leaders to place secret calls to his Chinese counterpart over concerns about then-president Donald Trump.
Milley's office pushed back against the report in the book, saying the calls he made as chairman of Joint Chiefs of Staff were co-ordinated within the Pentagon and across the US government.
According to excerpts of the book, Milley secretly called General Li Zuocheng of the People's Liberation Army twice in the final months of the Trump administration to say the US government was stable.
Milley reportedly told Li that the United States was not going to attack China and, if there were to be an attack, he would alert him ahead of time.
The excerpts were reported by the Washington Post on Tuesday.
The calls raised concerns that Milley may have subverted civilian control, but Biden defended him on Wednesday.
"I have great confidence in General Milley," Biden said.
Colonel Dave Butler, a spokesman for Milley, said Milley's calls with Chinese officials and others in October and January were in line with his responsibility to "maintain strategic stability".
"All calls from the chairman to his counterparts, including those reported, are staffed, co-ordinated and communicated with the Department of Defense and the interagency," Butler said in a statement.
"General Milley continues to act and advise within his authority in the lawful tradition of civilian control of the military and his oath to the Constitution."
He did not directly dispute the report on the contents of the calls.
The Pentagon strongly backed Milley as well.
"The secretary has complete and utter trust and confidence in General Milley and in his role as Chairman of the Joint Chiefs of Staff," Pentagon spokesman John Kirby told reporters, while declining to address the book's allegations.
The book, Peril, by journalists Bob Woodward and Robert Costa, which they said relied on interviews with 200 sources, is due to be released next week.
In a statement on Tuesday, Trump called the story "fabricated". If it was true, he said, Milley should be tried for treason.
"For the record, I never even thought of attacking China," Trump said.
Trump, a Republican, named Milley to the top military post in 2018 but began criticising him, as well as other appointees and former staffers, after losing the presidential election to Biden in November 2020.
According to the Washington Post, the book also says Milley called senior officers to review the procedures for launching nuclear weapons and told them that while the president alone could give an order to use them, he had to be involved.
"The meeting regarding nuclear weapons protocols was to remind uniformed leaders in the Pentagon of the long-established and robust procedures in light of media reporting on the subject," Butler said on Wednesday.
Australian Associated Press