Joe Biden says he's sorry for a 1998 comment referring to Bill Clinton's impeachment as a "partisan lynching." He had already tweeted an apology Tuesday, but offered a full-throated version in Fort Madison, Iowa, on Wednesday during a conversation with reporters.

"I was wrong to have said it. And I apologize for having said it," the former vice president said. "And I apologize for it then and I apologize for it now. The fact of the matter is it shouldn't be used at all, but the encouragement of white supremacists, which [Donald Trump has] done his entire presidency, that's what I was responding to. Because that's what it was. It was like a dog whistle...he's done it throughout — from Charlottesville on. When has he ever taken — when has he ever said a negative thing about a white supremacist? Have you heard anything? I haven't."

Biden was characterizing to President Trump's widely denounced use of the word Tuesday, when he likened his own impeachment inquiry to a "lynching."

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In October 1998, according to a report from CNN's KFILE, Biden said, "Even if the President should be impeached, history is going to question whether or not this was just a partisan lynching or whether or not it was something that in fact met the standard, the very high bar, that was set by the founders as to what constituted an impeachable offense."

"This wasn't the right word to use and I'm sorry about that," Biden tweeted Tuesday night. "Trump on the other hand chose his words deliberately today in his use of the word lynching and continues to stoke racial divides in this country daily."

Biden wasn't alone in referring to Clinton's impeachment proceedings as a lynching in 1998, according to The Washington Post. The Post identified at least five other lawmakers — Representatives Danny K. Davis, Gregory W. Meeks, Jim McDermott, Charles B. Rangel, and Jerrold Nadler — who also compared the Clinton proceedings to a "lynching," or referred to Clinton's opponents as a "lynch mob."

Representative Nadler, a New York Democrat, now chairs the committee that would consider articles of impeachment against Mr. Trump, the Post notes.

Biden was one of the many politicians who criticized Mr. Trump Tuesday for his comparison to lynching, a term often associated with the killing of African Americans during the Jim Crow era.

"So some day, if a Democrat becomes President and the Republicans win the House, even by a tiny margin, they can impeach the President, without due process or fairness or any legal rights. All Republicans must remember what they are witnessing here - a lynching. But we will WIN!" Mr. Trump tweeted.

"Impeachment is not 'lynching,' it is part of our Constitution," Biden tweeted Tuesday, before the KFILE report was published. "Our country has a dark, shameful history with lynching, and to even think about making this comparison is abhorrent. It's despicable."

Senator Susan Collins, a Maine Republican, tweeted that, "'Lynching' brings back images of a terrible time in our nation's history, and the President never should have made that comparison." Congressman Jim Clyburn, the House Majority Whip and a South Carolina Democrat, also spoke out against the president's tweet, saying he resents the lynching comment "tremendously."

"I think that what we see here once again is this president attempting to change the narrative, using what I consider to be real caustic terms in order to change the conversation," said Clyburn. "To compare the constitutional process to something like lynching is far beneath the office of president of the United States."

Bo Erickson contributed to this report.