01:22
European Council President Donald Tusk on Thursday said the US's unpredictability is a "real geopolitical problem". He was addressing a news conference at the EU-Western Balkans Summit in Sofia, Bulgaria. (TAKE SOT)
DONALD TUSK, PRESIDENT, EUROPEAN COUNCIL"I think that the real geopolitical problem is when you have not an unpredictable opponent or enemy or partner, the problem is when your closest friends is unpredictable. It's not a joke now."
Tusk also said US President Donald Trump's "unpredictability can be a very useful tool in politics, but only against enemies or opponents". He added that the EU has "the highest expectations when it comes to Washington".
This was the second time that Tusk make such comments on the US within the span of two days. On Wednesday, he urged leaders meeting in Bulgaria to unite economically, politically and also militarily.