Former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE lashed out at Sen. Lindsey Graham Lindsey Olin GrahamLincoln Project mocks Lindsey Graham's fundraising lag with Sarah McLachlan-themed video The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election Trump dumbfounds GOP with latest unforced error MORE (R-S.C.) on Friday after the Senate Judiciary Committee chairman asked the State Department to hand over any documents pertaining to the Bidens and Ukraine.

"I am disappointed and, quite frankly, I'm angered by the fact," Biden said on "CNN Tonight with Don Lemon Don Carlton LemonCNN's Don Lemon: 'Blow up the entire system' remark taken out of context CNN's Lemon: 'We're going to have to blow up the entire system' if Democrats win back White House, Senate Scaramucci to Lemon: Trump 'doubling down' on downplaying virus 'should scare' viewers MORE."

"He knows me. He knows my son. He knows there's nothing to this."

ADVERTISEMENT

When asked by Lemon what he would say to Graham if he saw him, Biden responded, "I'm just embarrassed by what you're doing, for you." He added that the South Carolina Republican is "about to go down in a way that I think he's going to regret his whole life."

Graham's focus on Biden and his son, Hunter Biden, comes as congressional Republicans have raised the issue repeatedly during the public impeachment hearings into President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE, who asked Ukrainian President Volodymyr Zelensky on a July 25 phone call to investigate Biden and his son’s dealings in Ukraine.

Republicans on the House Intelligence Committee have criticized Democrats for not investigating the Bidens and their connection to Ukraine. Hunter Biden served on the board of Burisma, a Kyiv-based natural gas holding company, while his father was vice president.

In 2016, Joe Biden pushed for the dismissal of Prosecutor General Viktor Shokin as prosecutor, citing concerns he was ignoring corruption in his own office, and threatened to withhold aid to Ukraine if the Shokin was not fired.

There is no evidence that Joe Biden was acting in the interest of his son, and he has consistently denied allegations that he was motivated by family considerations.

Trump, meanwhile, has pointed to debunked allegations that Ukraine interfered with the 2016 elections.

On Thursday, Trump's former National Security Council adviser on Russia, Fiona Hill, chastised Republicans for promoting the conspiracy theory.

"Please [do] not promote politically driven falsehoods that so clearly advance Russian interests," Hill said during her testimony. "The fictions are harmful even if they are deployed for purely domestic political purposes."