"I have felt very strongly that while Russia's actions had no impact at all on the outcome of the election, let me be totally clear in saying...that I accept our American intelligence community's conclusion that Russia's meddling in the 2016 election took place," the president said.
But, Trump added, "Could be other people also, there’s a lot of people out there."
Vice President Mike Pence and Secretary of State Michael Pompeo had a private conversation with Trump to urge him to make clarifications on his comments from the news conference in Helsinki, a source familiar with the conversation told NBC News.
The president came under widespread, bipartisan condemnation on Monday for not backing his intelligence community's assessment that Moscow had interfered in the election. The president made the comments in Helsinki just days after special counsel Robert Mueller indicted 12 Russian intelligence officials for meddling in the election, providing a detailed account of their hacking and other activities in the indictment.
During his Tuesday remarks, Trump also said that his administration took the threat of continued Russian interference seriously and vowed to move aggressively to "repel" any efforts by Moscow to interfere in future U.S. elections. "We’re doing everything in our power to prevent Russian interference in 2018," he said.
At the White House, Trump repeatedly ignored questions from NBC News' Peter Alexander about whether he would condemn Putin.
Democrats swiftly seized on the president's attempt to clarify his comments.
Senate Minority Leader Chuck Schumer, D-N.Y., accused Trump of trying to "squirm away" from his comments in Helsinki.
"President Trump tried to squirm away from what he said yesterday. It’s 24 hours too late and in the wrong place," Schumer said.
Sen. Mark Warner, D-Va., the vice chair of the Senate Intelligence Committee, said he wasn't buying it.
"I don't accept the president’s comments today," Warner said. "If he wanted to make those comments, he should have had the strength to make them in front of Vladimir Putin."
He added, "This has a strange resemblance to the president's comments after he was so offensive after the disturbances in Charlottesville where he equated the neo-Nazis with the protesters. So, I give these comments about 24 hours before he once again slams the investigation, before he once again sides with authoritarians like Vladimir Putin."
The president continued to defend his European trip on Wednesday morning, tweeting that "big results will come!" in a series of tweets.
Trump was pilloried from all sides on Monday, even from some staunch loyalists in his own party, for appearing to side with Putin over American intelligence agencies that have concluded that Russia interfered in the 2016 election.
Referring to the president's news conference with Putin, Sen. John McCain, R-Ariz., said Trump had "one of the most disgraceful performances by an American president in memory."
Former CIA director John Brennan, a frequent Trump critic and a national security analyst for NBC News and MSNBC, called Trump's performance "nothing short of treasonous." And former GOP House Speaker Newt Gingrich, a Trump confidant, called the president's comments "the most serious mistake of his presidency."
On Tuesday, Gingrich praised the president for clarifying his comments.
Despite the backlash against his remarks in Helsinki, Trump said on Tuesday that be thought the meeting he had with Putin was "really strong" and planned future meetings with him.
"I thought that the meeting that I had with President Putin was really strong. I think that they were willing to do things that frankly I wasn’t sure whether or not they would be willing to do," the president said. "And we'll be having future meetings and we’ll see whether or not that comes to fruition."