A new book by veteran Watergate reporter Bob Woodward says Donald Trump secretly sent coveted Covid-19 testing machines to Vladimir Putin for personal use when they were in short supply, a claim angrily dismissed by the Trump campaign.

The book - titled War- also includes a claim that Trump secretly has stayed in touch with Putin since leaving office, according to excerpts cited by US media.

The Trump campaign said none of these "made-up stories" were true.

“President Trump gave him absolutely no access to this trash book that either belongs in the bargain bin of the fiction section of a discount bookstore or used as toilet tissue,” said Trump campaign spokesperson Steven Cheung in a statement to the BBC.

The new book, due out next week, attributes the continuing communications between the former president and Putin to a single Trump aide who is not named in the book.

According to a report by the New York Times, the book describes one scene in which a Trump aide was ordered out of Trump’s office in Mar-a-Lago so the former president could conduct a call with Putin.

The unnamed aide reportedly said that the two may have spoken a half-dozen times since Trump left the White House in 2021.

The book does not say what they discussed, and it quotes a Trump campaign official casting doubt on the supposed contact.

The BBC has not seen a copy of the book. The Times reported that Mr. Woodward wrote that he could not corroborate the aide's claim and that other sources it reached out to were unaware of Trump and Putin contacting each other after he left office.

Woodward, who rose to fame for his role in uncovering the Watergate scandal that brought down Richard Nixon’s presidency, has written several best-selling books based on access to high-level sources.

Calling Woodward “demented” and “deranged”, Trump's campaign spokesperson said: "Woodward is an angry little man and is clearly upset because President Trump is successfully suing him because of the unauthorized publishing of recordings he made previously."

Trump had previously spoken to Woodward for the journalist's 2021 book - titled Rage. He later sued him over it, claiming Woodward did not have permission to release recordings of their interviews, an allegation denied by the author.

In War, Woodward writes that while the former president was in office, Trump “secretly sent Putin a bunch of Abbott Point of Care Covid test machines for his personal use”.

Putin was reportedly anxious about falling ill with the virus, according to the retelling of Woodward's book in US media.

The report adds that Putin had asked Trump not to publicly share that he had sent him the tests, fearful that it would damage Trump's reputation.

“I don’t want you to tell anybody because people will get mad at you, not me,” Putin reportedly told Trump, according to the book cited by the Times.

Trump reportedly said: “I don’t care. Fine.”

The claims have resurfaced questions about the relationship between Trump and Putin just weeks before the 05 November election.

The former president has been accused in the past of colluding with Russia to interfere with US elections, though a probe by the Department of Justice found no evidence of this and reached no conclusion as to whether Trump had obstructed the inquiry.

The book also examines the long shadow cast by Trump over the foreign conflicts of the past four years and over the bitter US political environment in which they have unfolded, according to the Washington Post.

It also includes candid assessments by President Joe Biden of his own missteps, including his decision to make Merrick Garland attorney general.

Reacting to the prosecution of his son Hunter — by a special prosecutor named by Garland — the president told an associate, “Should never have picked Garland", the Post reported.