Former US President Donald Trump asked an aide to leave the room so he could have a private call with Russian President Vladimir Putin, according to the latest book by famed Watergate reporter Bob Woodward.

In excerpts published Tuesday by The Washington Post, the writer says the current Republican White House candidate has maintained a personal relationship with the Kremlin boss even as Russia conducts a war against US ally Ukraine.

What does the book allege?

Woodward cites the unnamed aide suggesting Trump may have spoken to Putin as many as seven times since leaving the White House in 2021.

The aide, who Woodward does not name, said they were asked to leave the office while at Trump's Mar-a-Lago resort in Florida while he spoke to the Kremlin leader.

The upcoming book, titled "War," also reports that when he was president, Trump sent Putin COVID-19 tests for his personal use when the virus began to spread in 2020, despite a US shortage during the pandemic.

Woodward reports that Putin told Trump not to tell anyone because people would be upset with the then-US president. Trump reportedly said he didn't care if anyone knew, but ended up agreeing not to tell anyone.

Unfavorable comparison to Nixon

Woodward has chronicled US presidencies for five decades, and "War" is his fourth book since Trump's victory in 2016. 

He began his presidential reportages with Richard Nixon, who fell foul of the 1970s Watergate scandal that Woodward and his Washington Post colleague Carl Bernstein famously exposed.

In "War," Woodward concludes that Trump's interactions with Putin as an authoritarian president at war with a US ally, make him more unfit as an incumbent of the Oval Office than Nixon.

"Trump was the most reckless and impulsive president in American history and is demonstrating the very same character as a presidential candidate in 2024," Woodward writes.

Trump's relationship with Putin has faced scrutiny since his 2016 campaign to become president when the then-candidate urged Russia to find and make public missing emails deleted by his Democratic opponent, Hillary Clinton.

More recently, Trump has criticized US support for Ukraine as it fights off Russia's invasion. He has said Ukraine should have given concessions to Putin before Russia's military invaded in 2022.

Trump has also boasted of his good relationship with the Russian leader and said he was "pretty smart" for invading Ukraine.

Furious denial from Trump camp

Trump's communications director, Steven Cheung, denied the accounts in the book and issued a blistering criticism of Woodward for writing it. 

"None of these made up stories by Bob Woodward are true and are the work of a truly demented and deranged man who suffers from a debilitating case of Trump Derangement Syndrome," Cheung said in a statement.

"President Trump gave him absolutely no access for this trash book that either belongs in the bargain bin of the fiction section of a discount bookstore or used as toilet tissue. Woodward is a total sleazebag who has lost it mentally, and he's slow, lethargic, incompetent and overall a boring person with no personality."

In "War", Woodward also details President Joe Biden's frustrations with Israeli Prime Minister Benjamin Netanyahu. 

Biden's "frustrations and distrust" of Netanyahu "erupted" recently, Woodward wrote, with the president unleashing a profanity-laden tirade about the Israeli leader in private. 

rc/wmr (AFP, AP)