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President Donald Trump received messages of congratulations and concern from across the globe after he was sworn into office Friday, delivering an inaugural address that heavily emphasized an "America first" stance.

Japanese Prime Minister Shinzo Abe, Russian Prime Minister Dmitry Medvedev, Israeli Prime Minister Benjamin Netanyahu, and Mexican President Enrique Peña Nieto each expressed a desire to strengthen their countries' respective ties with the U.S, while Canadian Prime Minister Justin Trudeau said in a statement he looks forward to working with Trump "to restore prosperity to the middle class." Pope Francis encouraged Trump to be guided by America's "rich spiritual and ethical values." Others weighed in on Twitter:

Meanwhile, German Chancellor Angela Merkel, the de facto leader of the European Union, visited an art museum instead of listening to Trump's inaugural address, and German Vice Chancellor Sigmar Gabriel showed concern over Trump's "nationalistic tones." "I think we have to prepare for a rough ride," Gabriel said.