Giuliani digs into debunked Ukraine conspiracy theory after report Bolton called him a 'hand grenade' The president's personal lawyer responded Tuesday, standing by his Ukraine case.

President Donald Trump’s personal attorney Rudy Giuliani pushed back Tuesday against reports that Trump’s then-national security adviser John Bolton once referred to him as a “hand grenade,” insisting that others at the White House didn’t have the “evidence” he did of “Ukrainian collusion.”

Giuliani’s statement provided to reporters suggests the former mayor of New York and longtime Trump supporter isn’t backing down on his discredited claims that Ukrainian politicians tried to interfere in the 2016 election in favor of Democrat Hillary Clinton. U.S. intelligence agencies and officials have repeatedly said the concerted effort to meddle in the election came from Russia, not Ukraine, and favored Trump, not Clinton.

Citing recent testimony by witnesses, Democrats accuse Giuliani of running a shadow foreign policy operation to benefit the Trump campaign. Two Ukrainian-American businessmen who reportedly helped Giuliani to investigate Trump’s political rival, Joe Biden, and Biden’s son, Hunter, were indicted last week on campaign finance charges.

In testimony Monday on Capitol Hill, Trump’s former Russia adviser Fiona Hill quoted Bolton as saying that “Giuliani’s a hand grenade who’s going to blow everybody up,” according to The New York Times.

In a statement provided to ABC News on Tuesday, Giuliani said he was “disappointed” in Bolton for reportedly casting doubt on his claims.

“I’m not sure he realizes I received all this evidence as part of my representation of the President,” he said. “It was all part of the evidence, and suppression of evidence, involving Ukrainian collusion and the origin of some of the false information against the President.”

Last month, Trump’s former homeland security adviser Tom Bossert lashed out at Giuliani for promoting what he said was a “completely false” theory regarding Ukraine’s alleged interference in the 2016 election.

“At this point I am deeply frustrated with what [Giuliani] and the legal team is doing and repeating that debunked theory to the president,” Bossert, now an ABC contributor, said.

Giuliani has emerged as a central figure in the impeachment inquiry on whether Trump pushed Ukraine’s president to investigate his political rivals.

House lawmakers were hearing from a top State Department official on Tuesday, with other key witnesses – including Trump mega donor and hotelier-turned-diplomat Gordon Sondland -- scheduled to testify under subpoena on Thursday.

Guiliani’s business relationships remain the subject of an ongoing criminal investigation being conducted by federal authorities in New York.

Giuliani has acknowledged earning $500,000 for work he did with Lev Parnas, one of the two Ukrainian American businessman who were arrested last week and charged with campaign finance charges.

Giuliani told ABC News that he was retained by Parnas’ business “Fraud Guarantee” to do consulting work and insisted that any money he took came from domestic, not foreign sources.

Reached by ABC News, a spokesperson for Bolton, who left his post in September, declined to comment.