In a withering behind-the-scenes portrayal, President Donald Trump’s former national security adviser John Bolton accused him of sweeping misdeeds that included explicitly seeking Chinese President Xi Jinping’s help to win re-election.

Bolton, a long-time foreign policy hawk who Trump fired in September over policy differences, also said that the US President had expressed a willingness to halt criminal investigations to give “personal favours to dictators he liked”, according to a book excerpt published in the New York Times ahead of its release.

Trump hit back at Bolton, calling him “a liar” in an interview with the Wall Street Journal. The paper also published excerpts on Wednesday of the book, titled The Room Where It Happened: A White House Memoir, as did the Washington Post.

Trump told Fox News in a separate interview that Bolton had broken the law by including highly classified material in the book.

Together, the excerpts portray a US President mocked by his top advisers who exposed himself to far more extensive accusations of impropriety than those that drove the Democratic-led House of Representatives to impeach Trump last year.

The Republican-led Senate acquitted Trump in early February. Trump was accused of withholding US military aid last year to put pressure on newly-elected Ukrainian President Volodymr Zelensky to provide damaging information on Democratic political opponent Joe Biden.

“Had Democratic impeachment advocates not been so obsessed with their Ukraine blitzkrieg in 2019, had they taken the time to inquire more systematically about Trump’s behaviour across his entire foreign policy, the impeachment outcome might well have been different,” Bolton wrote, according to excerpts in the Wall Street Journal.

Critics of Bolton note he declined to testify before the House inquiry when his disclosures could have been critical.

Representative Adam Schiff, the California Democrat who led the prosecution of Republican Trump, slammed Bolton for saying at the time that “he’d sue if subpoenaed”.

“Instead, he saved it for a book,” Schiff said on Twitter. “Bolton may be an author, but he’s no patriot.”

Still, Bolton’s allegations provide new ammunition to critics ahead of the November 3 presidential election, including his behind-the-scenes accounts of Trump’s conversations with China’s Xi — which, in one case, broached the topic of the US vote.

“Trump then, stunningly, turned the conversation to the coming US presidential election, alluding to China’s economic capability and pleading with Xi to ensure he’d win,” Bolton wrote, in the most in-depth, damaging portrayal by a Trump administration insider to date and just days after former defence secretary Jim Mattis accused the President of trying to divide America.

China’s foreign ministry spokesman Zhao Lijian, asked about Bolton’s claims at a news briefing on Thursday, said China has no intention of interfering with the elections or internal affairs of the US.

Biden said in a statement: “If these accounts are true, it’s not only morally repugnant, it’s a violation of Donald Trump’s sacred duty to the American people.”

US trade Representative Robert Lighthizer said in Senate testimony that Bolton’s account was “absolutely untrue”.

“I was at the meeting. Would I recollect something as crazy as that? Of course I would,” Lighthizer said. “This never happened in it for sure. Completely crazy.”

The US government has sued to block Bolton from publishing the book, citing risks to national security, and is seeking a court hearing on Friday.

Although Trump’s administration had been strongly critical of China’s mass detention of mostly Muslim Uighur minority and other Muslim groups, Trump gave Xi a green light in June 2019 in Osaka, Japan, Bolton said.

“According to our interpreter, Trump said that Xi should go ahead with building the camps, which Trump thought was exactly the right thing to do,” Bolton wrote, adding another top White House official said Trump made similar comments during his 2017 trip to China.