"The 2020 presidential election is around the corner," Lee said as he accepted the prize for Best Adapted Screenplay for “BlacKkKlansman." "Let's all mobilize. Let's all be on the right side of history.
"Make the moral choice between love versus hate," he added. "Let's do the right thing!"
Trump slammed Lee on Twitter early Monday morning before leaving for his summit in Vietnam.
"Be nice if spike lee could read his notes, or better yet not have to use notes at all, when doing his racist hit on your president."
“BlacKkKlansman” closed with real news footage of the 2017 Charlottesville riots in which one person died and showcased how Trump refused to denounce white supremacy and nationalism following the tragedy.
While Lee was thrilled by his first competitive Oscars win (he previously won an honorary Oscar in 2015), he appeared displeased when "Green Book" took home Best Picture.
Lee was seen "throwing his hands in the air” and storming out of his seat as the cast of “Green Book” took to the stage to accept the award.
Backstage, Lee didn't hide his fury when he was asked by reporters to “tell us your thoughts on that Best Picture win.”
“Next question,” he replied.
No host at Sunday’s Oscars saw Queen + Adam Lambert kick things off to celebrate the band’s nominations for “Bohemian Rhapsody,” which took home four awards including Best Actor for Rami Malek’s portrayal of the late Freddie Mercury.
Despite no host, the show’s ratings were up 14 percent from 2018, which was a historic low for viewership.