Speaking to reporters in the United Kingdom on Friday before the indictments became public, Trump pledged to raise the 2016 election meddling issue during his sit-down with Putin.
Trump also told Britain's Daily Mail newspaper in the interview published on July 14 that he "fully intends" to run for reelection in 2020, adding that "it seems like everybody wants me to". "Our guy here is like an amateur boxer going up against Muhammad Ali".
Democrats have expressed concerns about Trump's ability to sit down and challenge Putin during a one-on-one meeting.
The lawmakers wrote that if Trump insists on meeting with the Russian president, that he should at least do so in the company of senior staff members so as not to be at a disadvantage to Putin.
"I think the European Union is a foe, what they do to us in trade", Trump said, adding that "you wouldn't think of the European Union, but they're a foe".
But Jon Huntsman, the United States ambassador to Russian Federation, says Monday's meeting "is really the first time for both presidents to actually sit across the table and have a conversation, and I hope it's a detailed conversation about where we might be able to find some overlapping and shared interests".
The summit, taking place at one of the most crucial junctures for the West since the 1991 fall of the Soviet Union, has perturbed some European allies who fear Mr Putin might seek a grand deal that undermines North Atlantic Treaty Organisation, the US-led transatlantic alliance.
But the Russian foreign ministry was delighted, jumping in through its official Twitter account to first "like" Trump's message then to retweet it with a clear response: "We agree".
"The main thing is zero collusion, and it has had an impact on the two largest nuclear powers in the world", he said. I think having meetings with the president of China was a very good thing, I believe it's really good.
Mueller has secured indictments against several former Trump campaign aides, including campaign chairman Paul Manafort, and former White House national security advisor Michael Flynn.