Biden: Lindsey Graham will 'regret his whole life' doing Trump's bidding on Ukraine

"Lindsey is about to go down in a way that I think he's going to regret his whole life," Biden told CNN's Don Lemon in an interview Friday in South Carolina.

Asked what he would say to Graham, who in the past had expressed his admiration for his long-time Senate colleague, Biden said: "I say Lindsey, I just -- I'm just embarrassed by what you're doing, for you. I mean, my Lord."

Graham, the Senate Judiciary Committee chairman, this week requested documents related to Biden and his son Hunter Biden's previous work in Ukraine. He is seeking documents from the State Department of Joe Biden's phone calls with former Ukrainian President Petro Poroshenko in February and March 2016 -- including whether there was any mention of the country's investigation into the business activities of Mykola Zlochevsky, who owned the natural gas company, Burisma Holdings, where Hunter Biden served on the board. There has been no evidence of wrongdoing by the Bidens.

"They have him under their thumb right now. They know he knows that if he comes out against Trump, he's got a real tough road for reelection, number one," Biden said of Graham.

"I am disappointed, and quite frankly I'm angered, by the fact -- he knows me; he knows my son; he knows there's nothing to this," Biden said. "Trump is now essentially holding power over him that even the Ukrainians wouldn't yield to. The Ukrainians would not yield to, quote, 'investigate Biden' -- there's nothing to investigate about Biden or his son."

In the interview, Biden also jabbed former New York City Mayor Michael Bloomberg, who has taken steps toward a late entrance into the 2020 Democratic presidential race, and former Massachusetts Gov. Deval Patrick, who recently entered the race.

The Bloomberg and Patrick candidacies were seen as a vote of no confidence from establishment Democratic donors in Biden's campaign.

Asked about concerns he can't carry the presidential race through to the finish line, Biden said, "Come on. I welcome the competition."

"Watch me. Watch me," Biden said. "The idea that I'm not in better shape than Mayor Bloomberg, physically and otherwise?"

"Look, this -- Trump is so bad as a President, and so corrupt as a President, that everybody in America who has ever been involved in politics, especially if they have a billion dollars, thinks they could beat Trump. Maybe they could," Biden said. "And so what do you have to do? I'm the guy sitting on the top of the pyramid. I get it. I'm a big boy. Never complain, never explain."

Biden also mentioned the lack of interest in Patrick's campaign in its early days. He pointed to an event Patrick had planned at Morehouse College on Wednesday that the former Massachusetts governor canceled after only two people were in the audience.

"He went down to Morehouse and had all these hundreds of seats, and no one showed up," Biden said.

"I like Deval. I really do. He's a good guy. He's a solid guy," he said. "But I think this is about deciding who is ready for day one to unite this country and demonstrate that they could, and number two, who in fact is ready on day one to be commander-in-chief."