Washington (CNN) German Chancellor Angela Merkel urged Harvard graduates Thursday to "tear down walls of ignorance and narrow-mindedness" in a speech that was an apparent rebuke of President Donald Trump's policies and worldview.

In her commencement address at the university, Merkel warned against the perils of isolationism and nationalism, pushed for action on climate change and said to never "describe lies as truth and truth as lies."

The Chancellor spoke in German and used a translator, but notably switched to English to close out her speech and said, "Tear down walls of ignorance and narrow-mindedness, for nothing has to stay as it is."

Merkel, who grew up in Soviet-controlled East Germany, said the tearing down of the Berlin Wall almost 30 years ago had allowed her to start her political career.

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