In a letter to national leaders before a summit that he will chair in Malta on Friday to prepare the Union's future after Britain leaves, the conservative former Polish prime minister said Trump's more protectionist trade policy offered the EU a chance and it should do more now to set up free trade deals.
Tusk's remarks were among the strongest directed at the new US president since Trump took office 11 days ago and reflects a growing sense in many European capitals of a need to respond to his policy moves, notably the ban at the weekend on the entry of refugees and others from seven Muslim-majority countries.
Leaders in Brussels have been particularly concerned that Trump has supported Brexit and spoken of other countries following Britain out of the bloc.
"The disintegration of the European Union will not lead to the restoration of some mythical, full sovereignty of its member states, but to their real and factual dependence on the great superpowers: the United States, Russia and China," Tusk wrote to the EU leaders, Reuters reported. "Only together can we be fully independent.
"We must therefore take assertive and spectacular steps that would change the collective emotions and revive the aspiration to raise European integration to the next level."
European diplomats said senior national officials and diplomats discussed a possible EU response to Trump at a meeting in Brussels on Monday. However, some governments were cautious that Europeans should not be hasty to alienate a key ally.