European Council President Donald Tusk says that "worrying declarations" from U.S. President Donald Trump's administration constitute part of an external threat faced by the European Union.
In a letter to EU heads of state and government published on January 31, ahead of a summit on February 3, Tusk called for unity in dealing with challenges he said were "more dangerous than ever before" in the history of the bloc.
He cited three threats, including an external one he said was "related to the new geopolitical situation in the world and around Europe."
Tusk said that an increasingly assertive China, "Russia's aggressive policy towards Ukraine and its neighbors, wars, terror and anarchy in the Middle East and in Africa, with radical Islam playing a major role, as well as worrying declarations by the new American administration all make our future highly unpredictable."
"For the first time in our history, in an increasingly multipolar external world, so many are becoming openly anti-European, or Euroskeptic at best," Tusk said in the letter. "Particularly the change in Washington puts the European Union in a difficult situation; with the new administration seeming to put into question the last 70 years of American foreign policy."
"We cannot surrender to those who want to weaken or invalidate the transatlantic bond, without which global order and peace cannot survive," he said. "We should remind our American friends of their own motto: United we stand, divided we fall."
Tusk also warned of an "internal threat" to the bloc, citing rising anti-EU, nationalist, and xenophobic sentiment in Europe.
The third threat identified by Tusk was the "state of mind of the pro-European elites" and "a decline of faith in political integration."
Trump has made numerous statements in recent months that have raised alarm in Europe. He supported the Brexit movement to take the United Kingdom out of the EU, a move that Trump described as "a tremendous asset."
"I do believe others will leave," he told The Times of London newspaper. "I do think keeping [the EU] together is not going to be as easy as a lot of people think."
Theodore Malloch, an economist who is widely expected to be Trump's choice for ambassador to the EU, said earlier this month that the euro common currency "could collapse" within 18 months. He also compared the EU to the Soviet Union.
"I had, in a previous career, a diplomatic post where I helped to bring down the Soviet Union," he told the BBC. "So maybe there's another union that needs a little taming."
Tusk's letter urged EU leaders to "take assertive and spectacular steps that would change the collective emotions and revive the aspiration to raise European integration to the next level."
Leaders of 27 European Union member states are scheduled to meet in Malta on February 3. A British delegation will only attend some sessions.