Former United States President and current Republican nominee Donald Trump has kept in regular touch with Russian President Vladimir Putin, according to new, unverified claims made by a celebrated journalist.

Bob Woodward, 81, alleges Trump made at least seven phone calls to the Russian leader since he left the Oval Office in January 2021.

One of the phone calls took place as recently as earlier this year, Woodward claims in his forthcoming book, War. Trump reportedly asked one of his aides to leave his office at his Mar-a-Lago estate so he could talk to the Russian leader.

The Trump campaign has rejected the allegations. Steven Cheung, the former president’s communications director, said on Tuesday that none of the stories in Woodward’s book was true.

Rather, he said, they were the “work of a truly demented and deranged man who suffers from a debilitating case of Trump Derangement Syndrome”.

Trump, 78, himself also denied the assertions. Speaking to ABC News, Trump said of Woodward: “He’s a storyteller. A bad one. And he’s lost his marbles.”

Reporter helped bring down Richard Nixon

Nevertheless, the claims delivered a jolt as the US prepares for its election on November 5. After all, Woodward is best known for the investigative reporting that helped bring down President Richard Nixon in 1974.

The book has also renewed concerns that Trump has had an improperly close relationship with the Russian leader.

Those allegations go back as far as 2016 when Trump first ran for president. At the time, he famously called on Russia to help find the “missing emails” his Democratic rival Hillary Clinton deleted from private servers.

The US intelligence community concluded that Moscow had interfered with the election to help Trump. However, an investigation by special counsel Robert Mueller found no conspiracy between the Trump team and Russia.

As he seeks a return to the White House, Trump has continued to boast of his friendship with Putin.

In 2022, Russia launched a full-scale invasion of Ukraine, something Trump has framed on the campaign trail as a consequence of faltering US leadership on the world stage.

He has claimed he could end the war in Ukraine in 24 hours, though supporters of Kyiv believe any such deal would require it to give up substantial territory to Russia, something Ukraine’s President Volodymyr Zelenskyy has rejected.

During the presidential debate last month, Trump declined to say if he believed it was in the US’s best interests for Ukraine to win the war.

“I want the war to stop. I want to save lives,” he said, adding incorrectly that “millions” had died. “I think it’s in the US’s best interest to get this war finished and just get it done.”

Woodward’s book, one of more than a dozen he has published over the years, also alleges Trump sent Putin COVID-19 test machines for his personal use as the virus began spreading in 2020.

The Russian leader is said to have asked Trump not to tell anyone as people would not be happy if word got out.

It is not clear when the machines were sent, but US media previously reported that the US had sent testing machines to several countries including Russia in May 2020.

Kamala Harris seizes on claims

The claims were seized on by Democratic candidate Kamala Harris.

In an interview with radio host Howard Stern, she accused Trump of giving the machines to a “murderous dictator” at a time when “everyone was scrambling” to get tests.

“This person who wants to be president again, who secretly is helping out an adversary while the American people are dying by the hundreds every day,” she said.

Aside from its hot-button revelations about Trump, Woodward’s book focuses on President Joe Biden’s handling of the war in Ukraine and the conflict in the Middle East.

It includes reports of Biden’s “frustrations and distrust” with Israeli Prime Minister Benjamin Netanyahu, who has led a deadly military campaign in Gaza since October 7, 2023.

Nearly 42,000 Palestinians have been killed in Gaza, with no ceasefire in sight and tensions expanding across the region.

The book says the US president in private called Netanyahu a “son of a bitch” and a “bad f***ing guy”.

It also indicates that Biden believes Netanyahu “had been lying to him regularly”.

Biden says Obama did not take Putin seriously

The book also claims Biden voiced criticism of his former boss, Democratic President Barack Obama, for failing to stop Putin’s invasion of Crimea in 2014. Biden served as vice president under Obama at the time.

“They f***ed up in 2014,” Biden allegedly said to a close friend, blaming the lack of response for Putin’s actions in Ukraine. “Barack never took Putin seriously.”

Asked about the book’s claims, White House spokesperson Emilie Simons told reporters, “The commitment that we have to the state of Israel is ironclad.”

She added of Biden and Netanyahu: “They have a long-term relationship. They have a very honest and direct relationship, and I don’t have a comment on those specific anecdotes.”