Donald Trump Says All He Can Say to Vladimir Putin About Russian Election Interference is 'Don't Do it Again'

President Donald Trump said Thursday that he would confront Russian President Vladimir Putin at an upcoming summit in Helsinki Monday over allegations that the country interfered in the 2016 presidential election. But he emphasized that he had limited tools at his disposal.

While multiple U.S. intelligence agencies have agreed that Russia was involved in a coordinated effort to influence the outcome of the 2016 presidential election, Trump said Thursday that if Putin continued to deny the allegations, there was little he could do.

"What am I going to do?" Trump said. "All I can do is say 'Did you?' and 'Don't do it again,'" Trump said, according to The Washington Post. "But he may deny it. You'll be the first to know." He added that Putin was "not my enemy" and "hopefully, someday, he'll be a friend. It could happen."

Trump's comments about the Russian president struck a very different tone from the combative language he aimed at countries he labeled "delinquent" at the annual NATO summit Wednesday. He complained in a tweet and at the summit that other members of the NATO alliance weren't contributing enough money to defense.

"Billions of additional dollars are being spent by NATO countries since my visit last year, at my request, but it isn't nearly enough. U.S. spends too much. Europe's borders are BAD! Pipeline dollars to Russia not acceptable," he tweeted.

Trump's presidency has been marked by intense interest in allegations of collusion between the Russian government and Trump's 2016 presidential campaign. The Department of Justice tapped former FBI Director Robert Mueller to lead an investigation into alleged Russian election meddling after Trump fired FBI director James Comey.

Trump has repeatedly decried the Mueller investigation. "There was No Collusion with Russia (except by the Democrats)," Trump tweeted in June. "When will this very expensive Witch Hunt Hoax ever end? So bad for our Country. Is the Special Counsel/Justice Department leaking my lawyers letters to the Fake News Media? Should be looking at Dems corruption instead?"

Earlier, in February, Trump tweeted that "Russia started their anti-US campaign in 2014, long before I announced that I would run for President. The results of the election were not impacted. The Trump campaign did nothing wrong- no collusion!"

Trump has met with Putin on a few occasions since he took office. In November, after a brief meeting with Putin at the APEC summit in Vietnam, Trump said of the Russian president, "He said he didn't meddle. You can only ask so many times. I just asked him again. He said he absolutely did not meddle in our elections."

"Every time he sees me he says, 'I didn't do that,'" Trump said of his belief that Putin is telling the truth. "And I really believe that when he tells me that, he means it."