BRUSSELS – President Donald Trump’s recent declarations about potentially annexing Greenland and imposing tariffs on its supporters have sparked significant concern across Europe. According to a senior EU official, these actions challenge the core values and security of Europe.

European Council President António Costa, in light of these developments, has called for an urgent summit with the EU’s 27 national leaders. This meeting, set to take place in Brussels on Thursday, aims to address what Costa describes as a critical testing of transatlantic relations.

Trump’s ambition to “acquire” Greenland, rich in mineral resources and strategically located in the Arctic, is ostensibly for security reasons. However, this move has strained trust between the United States and its allies in Europe and Canada.

The tension escalated when Denmark, which administers Greenland as a semiautonomous territory, deployed a military “reconnaissance” force to the island. This action, supported by troops from several European countries, has led Denmark to consider establishing a more permanent military presence in Greenland.

In response, Costa emphasized the EU’s commitment to the principles of international law, territorial integrity, and national sovereignty. These principles have been central to the EU’s stance against Russia’s invasion of Ukraine and are now relevant to the situation in Greenland.

Addressing members of the European Parliament in Strasbourg, France, Costa underscored the importance of self-determination, stating that “only Denmark and Greenland can decide their future.”

He insisted that “further tariffs would undermine transatlantic relations and are incompatible with the EU-US trade agreement.” The lawmakers must endorse that deal made last July, but have threatened not to do so over Trump’s tariff threats.

Costa said that “we stand ready to defend ourselves, our member states, our citizens, our companies, against any form of coercion. And the European Union has the power and the tools to do so.”

EU leaders have been galvanized by Trump’s threats over Greenland, and are rethinking their relations with America, their long-time ally and the most powerful member of NATO.

“Appeasement is always a sign of weakness. Europe cannot afford to be weak — neither against its enemies, nor ally,” Polish Prime Minister Donald Tusk, long a staunch supporter of strong transatlantic ties, posted on social media on Tuesday.

“Appeasement means no results, only humiliation. European assertiveness and self-confidence have become the need of the moment,” Tusk wrote.

European Commission President Ursula von der Leyen, who manages trade on behalf of EU countries, warned that the bloc is “at a crossroads.” Should tariffs come, she said, “we are fully prepared to act, if necessary, with unity, urgency and determination.”

In Strasbourg, she told the lawmakers that the commission is working on “a massive European investment surge in Greenland” to beef up its economy and infrastructure, as well as a new European security strategy.

Security around the island itself should be boosted with partners like the U.K., Canada, Norway and Iceland, among others, von der Leyen said.