Donald Trump's election victory risks upsetting the relationship between the European Union and the United States, the president of the European Commission has said.

Speaking to students at a conference in Luxembourg on Friday, Jean-Claude Juncker said the 70-year-old former reality TV star was ignorant of the EU and its workings, and would "waste time for two years" while touring a world "he is completely unaware of".

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"The election of Trump poses the risk of upsetting intercontinental relations in their foundation and in their structure," said Juncker, one of Europe's most powerful political figures.

Juncker also warned against the "pernicious" consequences of Trump's statements on security policy.

He also recalled a Trump statement in which he seemed to think that Belgium, the country that hosts the headquarters of the EU and NATO, was a city.

"We will need to teach the president-elect what Europe is and how it works," Juncker said, adding that Americans usually had no interest in Europe.

"I think we will waste two years before Mr Trump tours the world he does not know," said Juncker, who on Thursday had already raised doubts about Trump's views on global trade, climate policy and Western security.

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Juncker's comments contrasted with the more diplomatic reactions of other European leaders, who said they looked forward to working with the next Republican president.

Within hours of the Republican's surprise win, EU Council President Donald Tusk said that despite the talk of protectionism and isolationism by Trump's campaign, both sides "should consolidate the bridges we have been building across the Atlantic".

Federica Mogherini, the EU's foreign policy chief, said on Twitter that "EU-US ties are deeper than any change in politics. We'll continue to work together, rediscovering the strength of Europe".

Meanwhile, among Trump's main supporters, and some of the first to wish him well in his new role, were France's far-right leader Marine Le Pen, who heads the National Front; Viktor Orban, Hungary's prime minister; and Geert Wilders, the Dutch politician who believes Muslim immigration should be halted.

Source: Al Jazeera News And News Agencies