"Blocking roads, regardless of political intentions, poses a threat to the state and all road users," Tusk said on social media earlier this week.
He added that he had instructed "the appropriate services to respond decisively and counteract such actions."
Interior Minister Tomasz Siemoniak announced that police would take a firm stance against "this kind of pathological behaviour."
For over a week, climate activists have been blocking major roads in the Polish capital during morning rush hour.
Radio Poland's Michał Owczarek has the details.
Click on the audio player above to listen.