US President Donald Trump on Sunday urged Special Counsel Robert Mueller to disclose his conflicts of interest in pending investigation.

"Is Robert Mueller ever going to release his conflicts of interest with respect to President Trump, including the fact that we had a very nasty & contentious business relationship, I turned him down to head the FBI (one day before appointment as S.C.) & [former FBI Director James] Comey is his close friend," US President Donald Trump said on Twitter on Sunday.

?The US president went on to criticize Mueller over "only appointing Angry Dems" and failure to look at alleged "criminal activity & real Russian Collusion on the Democrats side."

Trump stressed that there had been no collusion between his campaign and the Russian government and reiterated his claim the probe was a witch hunt.

Trump has repeatedly turned to Twitter to try to bend proceedings and public opinion in the direction he would like — calling for Mueller’s probe to end and demanding that the Justice Department investigate his political enemies.

In one of many similar tweets, Trump on April 20 appeared to try to undermine Mueller’s probe into whether the Trump campaign colluded with Russia in its efforts to skew the 2016 US presidential election.

A Republican-controlled Senate panel has said recently that further evidence has been found to support a US intelligence assessment that Russia interfered in the 2016 presidential election to help elect Donald Trump.

Meanwhile, a group of Republican lawmakers on Wednesday introduced articles of impeachment to remove deputy U.S. Attorney General, Rod Rosenstein, escalating a fight over Special Counsel Robert Mueller’s investigation of alleged Russian meddling in the 2016 U.S. presidential election.

A special counsel, Robert Mueller,  is investigating possible collusion between Russia and members of Trump’s campaign team. Three campaign aides have pleaded guilty to lying to the FBI and Trump’s former campaign chief, Paul Manafort, is in jail awaiting trial on charges of financial crimes.