President Trump on Wednesday called on Republicans to "take control" of the investigation into whether his campaign colluded with Russia and labeled the ongoing probe the "single greatest Witch Hunt in American history."

"There was no collusion, everybody including the Dems knows there was no collusion, & yet on and on it goes. Russia & the world is laughing at the stupidity they are witnessing. Republicans should finally take control!" Trump tweeted.

Trump has repeatedly labeled special counsel Robert Mueller's investigation a witch hunt and has denied colluding with Russia during the presidential race. Last month Trump said even if there was collusion, "it's not a crime." He has also suggested the FBI instead investigate his 2016 opponent, Democratic nominee Hillary Clinton.

In a tweet earlier Wednesday, Trump lashed out at Sen. Dianne Feinstein (D-Calif.) for unilaterally releasing the full transcript of an interview between congressional investigators and the co-founder of the opposition research firm that commissioned a controversial dossier on Trump during the 2016 campaign.

Democrats have claimed the dossier to be a roadmap to alleged collusion and corruption by Trump and his officials, while Republicans insist that it is full of unverified claims that the FBI might have used to improperly secure a warrant to spy on Trump's campaign and transition.

Sen. Chuck Grassley (R-Iowa), who chairs the Senate Judiciary Committee, said he's not sure what the president had in mind with his comments, adding that he doesn't plan to follow up with Trump on the matter.

"I don't intend to have a discussion with the president on that point and I hope he doesn't call me and tell me the same thing that you said he said," Grassley told CNN's Manu Raju on Wednesday when told about Trump's tweet.

The Judiciary Committee is one of several congressional committees conducting separate investigations into Russian meddling in the 2016 election.

Some GOP lawmakers have in recent weeks accused the Mueller probe of bias against the president, citing anti-Trump text messages sent by a former member of Mueller's team.

It was recently reported that Trump's team is discussing options for a possible interview with Mueller in the coming weeks.

Mueller's investigation has thus far led to two indictments and two guilty pleas.

Former Trump campaign chairman Paul Manafort and his former associate, Richard Gates, were indicted on money laundering and tax fraud charges, among others.

Former White House national security adviser Michael Flynn and former Trump campaign policy adviser George Papadopoulos pleaded guilty to lying to the FBI.

Updated: 11:57 am.