The first vice president of the European Commission has attacked nationalism, saying the ideology makes countries weaker, poorer, and morally insecure.
Frans Timmermans compared the ideology and what he called its 'Siamese twin' of protectionism to alcohol dependency, saying they create 'a short period of exaltation followed by a long period of headaches.'
While striding through war graves in Europe, Mr Timmermans argued that nationalists cannot be true patriots because they undermine their home countries.
Frans Timmermans, the first vice president of the European Commission, launched a scathing attacking on nationalism, saying it makes countries 'weak'
Mr Timmermans released the video to commemorate Black Ribbon Day, which remembers the victims of totalitarian regimes in Europe.
He posted the video message to Facebook, along with the caption: 'European cooperation, patriotism and our values make us who we are.
'Let's reject extreme nationalism which weakens member states individually and collectively.
'Nationalists are un-patriotic. A true patriot is proud of his nation, needs unity, openness, cooperation with others, the strength found in compromise and debate.
Mr Timmermans, who was commemorating European victims of totalitarian regimes, said nationalists could never be true patriots
'Today, on the European Day of remembrance for victims of all totalitarian and authoritarian regimes, I want to send a clear message that to be a patriot is to be European, to be European is to be a patriot.'
A spokesman for the commission later had to clarify that Mr Timmermans had not been talking directly about Brexit.
Earlier in the day it was revealed that European courts could have jurisdiction over the UK for three years under a transitional arrangement following Britain's departure from the EU.
The deal was exposed despite Prime Minister Theresa May championing the Conservative pledge to take back control of British law after Brexit.
The proposal was contained in a paper laying out possible options for Britain's future legal relationship with the European Union after March 2019.