U.S. President Donald Trump met the heads of European Union institutions in Brussels on ahead of a summit of NATO.

Brussels was the fourth destination of Trump, on his foreign trip to Middle East and Europe. He was greeted by European Council President Donald Tusk, a former Polish prime minister who chairs meetings of the EU heads of states and governments. The European Commission President Jean-Claude Juncker joined the talks.

The meeting is particularly challenging for Tusk, who openly supported #Hillary during the US elections. “One Donald is enough” – he wrote in a tweet, ‘quoting’ his spouse. When president Trump was elected, Tusk continued his ‘anti-Trump’ rethoric, and sent around an open  letter to the EU member-states, using his position of the chair of the EU Council, warning against the US president as an ‘existential threat’ to the European Union, launching an unprecedented attack on the US administration. Incumbent Polish government opposed the second mandate of Tusk, however he got the position due to voting procedure.