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Three top Democrats issued a warning to President Donald Trump on Sunday, saying he cannot "discourage, intimidate, or otherwise pressure" witnesses in response to his Saturday comments about his former attorney Michael Cohen.

"The integrity of our process to serve as an independent check on the Executive Branch must be respected by everyone, including the President," Democratic chairmen Elijah Cummings, Adam Schiff and Jerrold Nadler of the House Oversight, Intelligence, and Judiciary Committees said in a joint statement.

"Our nation’s laws prohibit efforts to discourage, intimidate, or otherwise pressure a witness not to provide testimony to Congress. The President should make no statement or take any action to obstruct Congress’ independent oversight and investigative efforts, including by seeking to discourage any witness from testifying in response to a duly authorized request from Congress."

The congressmen were responding to comments Trump made Saturday to Fox News host Jeanine Pirro in response to news of Cohen's upcoming open testimony before the House Oversight Committee.

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Trump told Pirro that Cohen "should give information maybe on his father-in-law, because that’s the one that people want to look at."

"Because where does that money — that’s the money in the family. And I guess he didn’t want to talk about his father — he’s trying to get his sentence reduced," Trump added. "So, it’s pretty sad. You know, it’s weak and it’s very sad to watch a thing like that. I couldn’t care less."

The comments echoed remarks Trump made on Twitter in December just prior to Cohen's sentencing hearing. Trump said Cohen should serve a "full and complete" prison sentence, adding that his former lawyer "makes up stories to get a GREAT & ALREADY reduced deal for himself, and get his wife and father-in-law (who has the money?) off Scott Free."

Last week, Cohen agreed to testify publicly before the Oversight Committee in February prior to the start of his prison sentence. "I look forward to having the privilege of being afforded a platform with which to give a full and credible account of the events which have transpired," he said in a statement.

Reached by NBC News Sunday, Cohen responded to a question about Trump's comments by passing along a link to the Democrats' statement. Lanny Davis, Cohen's legal adviser, declined to respond to Trump's remarks when asked by NBC News.

In December, Cohen was sentenced to three years in prison for what a Manhattan federal court judge called a "veritable smorgasbord" of criminal conduct, including making secret payments to women who claimed they had affairs with Trump, lying to Congress about the president's business dealings with Russia and failing to report millions of dollars in income.

Two of the nine felony counts Cohen has pleaded guilty to involved the payments to women, which he helped facilitate in the weeks leading up to the 2016 presidential election.

Cohen also pleaded guilty to a single count of making false statements to Congress about the scope and status of the Trump Tower Moscow project.

Trump has denied any affairs and said Cohen is a liar. Following Cohen's sentencing, Trump defended his efforts to build a Trump-branded tower in Russia while running for president of the United States as "very legal" and "very cool."