"There has been no collusion between the Trump campaign and Russians, or Trump and Russians," the president said at a news conference with Norwegian Prime Minister Erna Solberg.
Trump then changed the subject to Hillary Clinton, his Democratic opponent in the 2016 presidential race.
Pressed again as to whether he would meet with Mueller's team, Trump again said, "We'll see what happens," before suggesting that he might not need to be interviewed at all.
"When they have no collusion, and nobody has found any collusion at any level, it seems unlikely that you would even have an interview," he said.
Trump's equivocating answer was a stark departure from the hard-charging optimism he expressed in June of last year, when he said he would be "100 percent" willing to testify under oath as part of the investigation.
In the months since then, Trump's former national security advisor and campaign aide, Michael Flynn, has pleaded guilty to lying to federal investigators, as has another of Trump's former campaign aides. His former campaign manager, Paul Manafort, and Manafort's longtime associate, Rick Gates, have both been indicted on multiple counts related to money laundering.