US President Donald Trump at the White House campus. Picture: Evan Vucci/AP

Washington - US President Donald Trump said Monday that he had the power to pardon himself in the Russia collusion affair, as well as reiterating his claim of innocence in the special counsel investigation. "As has been stated by numerous legal scholars, I have the absolute right to PARDON myself, but why would I do that when I have done nothing wrong?" Trump wrote on Twitter early Monday.

Special Counsel Robert Mueller is investigating whether Russia interfered in the 2016 presidential election, whether Russian officials had contact with members of Trump's campaign and whether the president is guilty of obstruction of justice. 

Trump went on to say Mueller's appointment by Deputy Attorney General Rod Rosenstein in May 2017 was in breach of the US constitution. "The appointment of the Special Councel [sic] is totally UNCONSTITUTIONAL! Despite that, we play the game because I, unlike the Democrats, have done nothing wrong!" Trump wrote on Twitter.

The question of self-pardon arose after the New York Times published a letter from Trump's lawyers to Mueller in which they argued he could not be indicted, subpoenaed or found guilty of obstruction of justice due to his position as the country's chief law enforcement officer.

One of Trump's lawyers, Rudy Giuliani, used a series of interviews late Sunday to argue that the only action that could be taken against his client was impeachment.

"In no case can he be subpoenaed or indicted," Giuliani told the Huffington Post. "I don't know how you can indict while he's in office - no matter what it is."