"The Mueller report strongly stated that there was No Collusion with Russian Federation", he tweeted. "No redos for the Dems!"
Mueller set forth 10 instances in which Trump sought to thwart the investigation, but the former FBI director did not reach a conclusion on whether a crime was committed. Nadler threatened Friday to hold Barr in contempt if he did not comply with a final request to turn over the Mueller report and the relevant investigative materials.
The Mueller report chronicled Russian efforts to help Trump win election in 2016 but found that Trump and his campaign did not engage in a criminal conspiracy with Moscow.
The letter is the latest pushback from Democrats against Barr since the release of the Mueller report.
Mr Trump said he was "elected to represent the citizens of Pittsburgh, not Paris".
"Their chief complaint against the attorney general is his upholding the rule of law when they wish him to disregard it", he said.
Trump told reporters in the Oval Office last week that testimony from Mueller was "up to our attorney general".
"Lastly, it can not go unremarked that, in refusing to comply with congressional oversight requests, the department has repeatedly asserted that Congress's requests do not serve "legitimate" purposes", Nadler wrote. Then, on March 24, Democrats and the media learned not only that there was no collusion case (which was no surprise) but that Mueller had been derelict, failing to render a judgment on the only question he was arguably needed to resolve: Was there enough evidence to charge obstruction?
Democrats raised the prospect of holding him in contempt after the department also missed the House Judiciary Committee deadline to provide it with a full, unredacted version of Mr Mueller's report and its underlying evidence. Dated March 27, the letters expressed Mueller's frustration Barr didn't release the executive summaries prepared by the special counsel's team.
Barr, speaking before the Senate Judiciary Committee this week, said he had a 15-minute phone call with Mueller after the special counsel sent the letter. But he said in a later tweet that he had misspoken. William Barr has said he has no objection to Mueller testifying. That's the date the Committee has proposed, and we hope the Special Counsel will agree to it. And he stood by that claim when he appeared before the Senate Judiciary Committee. He repeatedly denied accusations and insinuations by Democrats that he had lied or misrepresented anything.
"I don't know", Barr answered. That's from David Cicilline (D-R.I.), who reported the news on Fox News, according to Axios. We gave hundreds of people. Joe wants to cut the president down to size, and Bill Barr wants to protect the president from Democrats like Joe Biden. I wouldn't say suggest...
While Trump continues to criticize journalists and call the news "fake", the Mueller report reveals a number of lies, changed stories and misleading statements by Trump and his affiliates.
Trump repeatedly tried other tactics to sabotage Mueller's investigation. White House attorney Emmett Flood wrote, in a letter made public Thursday, that Trump's decision to waive privilege for the Mueller investigation did not prevent him from invoking privilege in relation to a congressional investigation.