The protesters had gathered outside the White House just as the president was returning from his meeting abroad.
Video and photos from the rally show protesters chanting "Putin's puppet" and "traitor" and carrying signs that read "liar."
It is unclear how many people joined the protest, though people in attendance said there were "hundreds" who came on last-minute notice for the rally.
Some protesters say they plan to continue protesting outside the White House until Trump resigns.
The impromptu protest, dubbed #OccupyLafayettePark, came after Trump's controversial press conference with Putin. During the joint presser, Trump refused to denounce Russia's 2016 election meddling and said both countries were to blame for the current low point in U.S.-Russia relations.
Trump's comments sparked immediate backlash from lawmakers and political commentators on both sides of the aisle.
On Friday, special counsel Robert Muller indicted 12 Russian intelligence officers for allegedly hacking Democratic officials and entities during the 2016 presidential race.
Many had called on Trump to confront Putin about the indictments during their meeting in Helsinki.
Instead, Trump said during the news conference that he doesn't see any reason why Russia would interfere in the United States' presidential election, pointing to Putin's denials.
"He just said it’s not Russia,” Trump said. “I will say this, I don’t see any reason why it would be.”
