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President Donald Trump directed his former national security adviser John Bolton to help with his pressure campaign in Ukraine to dig up dirt on Democrats in early May last year, according to a draft manuscript by Bolton reported on by The New York Times.

According to Bolton’s account, Trump told him to call Ukrainian President Volodymyr Zelensky to make sure the newly elected leader would meet with his personal lawyer, Rudy Giuliani, the Times reported.

On Friday, Trump denied the allegation in a statement.

“I never instructed John Bolton to set up a meeting for Rudy Giuliani, one of the greatest corruption fighters in America and by far the greatest mayor in the history of N.Y.C., to meet with President Zelensky,” Trump said. “That meeting never happened.”

CNN has not seen a copy of the draft manuscript. The report would be the earliest known instance of Trump actively trying to exert political pressure on Ukraine in order to find damaging information on his political opponents.

Trump’s attempts to pressure Ukraine to investigate Hunter Biden and Joe Biden, his potential 2020 general election rival, are at the center of the President’s impeachment trial. Trump and his allies have repeatedly made unfounded and false claims to allege that the Bidens acted corruptly in Ukraine.

Bolton writes that he never made the call to Zelensky, the Times reports.

He claims Trump’s request came during an Oval Office conversation that included Giuliani, acting White House chief of staff Mick Mulvaney, and the White House counsel Pat Cipollone, according to the Times. Cipollone has been leading the President’s defense team in the impeachment trial.

Giuliani denied the report to the Times, and neither Bolton, a representative for Mulvaney, nor the White House immediately responded to requests for comment to the paper.

The allegation from Bolton’s unpublished draft comes as Republicans appear to have enough support for the Senate trial to wrap up, without hearing from witnesses or subpoenaing documents. Bolton has said he’s willing to testify if subpoenaed.

The Times had previously reported that Bolton alleges in his forthcoming book that Trump told him over the summer that he wanted to continue holding military aid to Ukraine until the country helped with investigations into his political rivals.

A source with direct knowledge of the manuscript has told CNN the newspaper’s telling of Bolton’s discussion with Trump is accurate.

The White House has attempted to block Bolton from publishing his book, which is planned for March, saying it contains classified information.

Democrats had also pushed for Mulvaney to testify and point to his October press conference, in which he admitted – and then denied – a quid pro quo that Trump help up $400 million in US security aid to Ukraine in exchange for an investigation into Democrats. The President’s defense has argued that that there was no quid pro quo, that the President had other motives for withholding the aid, and that the aid was ultimately released.

Giuliani traveled to Ukraine in May to pursue questions about the Bidens’ ties to a Ukrainian natural gas company.

He and his associates mounted a smear campaign to remove former US ambassador to Ukraine Marie Yovanovitch from her post in Kiev, viewing her as an impediment to obtain information about Biden from his Ukrainian sources.

This story has been updated.

CNN’s Kaitlan Collins contributed to this report.