The rules-based world order "no longer exists", German Chancellor Friedrich Merz warned at the Munich Security Conference. Opening the annual summit, he told world leaders that "our freedom is not guaranteed" in an era of big power politics, and that Europeans must be ready to make "sacrifice". He admitted that "a deep divide has opened between Europe and the United States". The conference takes place as US President Donald Trump threatens Denmark's sovereignty over Greenland and imposes tariffs on European imports. US Secretary of State Marco Rubio, who will speak on Saturday, earlier spoke of a "new era in geopolitics". Some 50 world leaders are expected to attend, discussing European defence and the future of transatlantic ties, amid questions over US commitments to NATO. Merz cited former US Vice-President JD Vance's critical speech from a year ago, agreeing a divide exists but stating Europe's culture war and protectionism differ. He appealed to "repair and revive transatlantic trust". Merz also revealed "confidential talks" with French President Emmanuel Macron on a joint European nuclear deterrent. Ahead of the conference, Rubio warned the world is changing fast, requiring a re-examination of roles. Tensions have risen as Trump repeatedly claims Greenland is vital to US security and is negotiating for it, prompting Danish PM Mette Frederiksen to plan a meeting with Rubio.