President Donald Trump probably has the power to pardon himself but does not plan to do so, his attorney Rudy Giuliani said. Picture: AP Photo/Evan Vucci

Washington - President Donald Trump, under pressure from special counsel Robert Muller's investigation into Russia's role in the 2016 US election, probably has the power to pardon himself but does not plan to do so, his attorney Rudy Giuliani said on Sunday.

Asked whether Trump has the power to give himself a pardon, Giuliani said, "He's not, but he probably does." Giuliani added that Trump "has no intention of pardoning himself," but that the US Constitution, which gives a president the authority to issue pardons, "doesn't say he can't."

Speaking on ABC's "This Week" programme, Giuliani added, "It would be an open question. I think it would probably get answered by, gosh, that's what the Constitution says."

Giuliani also said it is an "open question" whether Trump would sit for an interview with Mueller but that the president's lawyers were leaning against having him testify.

Mueller is investigating whether Russia meddled in the presidential election and whether Trump campaign's colluded with Moscow. Mueller, whose investigation already has led to criminal charges against Trump campaign aides including former campaign chairman Paul Manafort, is also looking into whether Trump unlawfully sought to obstruct the Russia investigation.

Both Russia and Trump deny collusion, and the president has denied obstructing the probe.

Trump's lawyers argued in a letter to the special counsel that the president could not have obstructed the probe given the powers granted to him by the Constitution, the New York Times reported on Saturday.

In the January 29 letter, Trump's lawyers contended that the Constitution gives the president the power to "terminate the inquiry, or even exercise his power to pardon," the Times reported.

House of Representatives Majority Leader Kevin McCarthy, a Republican, made clear that he did not think Trump or any other president should pardon himself.

"I don't think a president should pardon themselves," McCarthy told CNN's "State of the Union" programme.

Trump has not been shy about using his pardon power.

The president on Thursday pardoned conservative commentator and filmmaker Dinesh D'Souza, who pleaded guilty in 2014 to US campaign finance law violations. Trump also said he was considering pardoning lifestyle maven Martha Stewart and commuting the prison sentence of former Illinois Governor Rod Blagojevich, convicted of corruption charges. Critics accused Trump of subverting the rule of law.