President Trump unloaded on former House Speaker Paul Ryan for the second time in three days Saturday, mocking him as a "Lame Duck" and chiding his leadership style as "ineffective" and "stupid."

In a series of tweets, Trump praised House Minority Leader Keven McCarthy, R-Calif., calling him smarter and tougher than Ryan, who retired in January. He also characterized Ryan's fundraising numbers in his final year in office as "abysmal" and said people like him "almost killed the Republican Party."

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"House Minority Leader Kevin McCarthy is a far superior leader than was Lame Duck Speaker Paul Ryan. Tougher, smarter and a far better fundraiser, Kevin is already closing in on 44 Million Dollars. Paul’s final year numbers were, according to Breitbart, 'abysmal,'" Trump posted.

His comments come days after excerpts from an upcoming book the former House Speaker as saying that Trump “didn’t know anything about government” and that Ryan wanted to “scold him all the time.”

“Because I’m telling you, he didn’t know anything about government . . . I wanted to scold him all the time," Ryan reportedly said in the book, "American Carnage" by Politico reporter Tim Alberta. “Those of us around him really helped to stop him from making bad decisions. All the time. We helped him make much better decisions, which were contrary to, kind of, what his knee-jerk reaction was. Now I think he’s making some of these knee-jerk reactions.”

Ryan recalled a difficult working relationship with Trump, during which he refused to endorse some of the president's more controversial policies such as a proposed travel ban affecting several Muslim-majority countries, as well as Trump's hardline immigration policies.

Alberta writes that Ryan couldn't stand the thought of another two years with Trump and saw retirement as an "escape hatch," according to The Washington Post, which obtained a copy of the book.

Late Thursday, Trump said that Ryan, who served in the House of Representatives for almost two decades, "quit Congress because he didn’t know how to Win."

"Paul Ryan, the failed V.P. candidate & former Speaker of the House, whose record of achievement was atrocious (except during my first two years as President), ultimately became a long running lame duck failure, leaving his Party in the lurch both as a fundraiser & leader..." Trump tweeted.

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Trump hasn't always been hostile toward the former GOP leader. When the Ryan and 2012 vice presidential candidate announced he would not seek re-election in 2018, Trump wished him well over Twitter.

"Speaker Paul Ryan is a truly good man, and while he will not be seeking re-election, he will leave a legacy of achievement that nobody can question," he posted at the time. "We are with you Paul!"