A three-day global security conference with US Vice President Joe Biden as the top speaker was to start in Germany Friday, focusing on Mali, Syria and other world trouble spots.
Biden was set to meet German Chancellor Angela Merkel in Berlin on Friday before heading Saturday to the Munich Security Conference (MSC), where he was to speak on trans-Atlantic relations.
Ahead of the MSC, which groups some 400 heavyweights from the worlds of defence and diplomacy, Biden set out key US foreign policy objectives in an interview with the Suddeutsche Zeitung daily.
Biden rejected the notion that the United States was strategically shifting from Europe toward Asia and said trans-Atlantic ties remained "the pillar of all our responsibilities in the world."
He also reiterated the Obama administration's earlier offer of direct talks with Iran over its nuclear programme but warned that the diplomatic "window will not stay open indefinitely."
Biden - on his first trip abroad since President Barack Obama started his second term - vowed that the US would prevent Iran from building a nuclear weapon which would present a "national security threat" to the US.
In his meeting with Merkel, Biden was also expected to address efforts toward reaching an eventual US-European free trade deal, and discuss a possible Obama visit to Berlin this year.
On Saturday he was to address the MSC, which brings together about a dozen heads of state and government, 70 ministers as well as leaders from defence and business, including the arms industry.
Heavy police security was in place, with some 3,400 officers guarding the conference starting Friday 1400 GMT in the centre of Munich, where peace activists planned to stage a protest Saturday.
The UN-Arab League Syria envoy Lakhdar Brahimi was to take part in an evening session, along with Moaz Al-Khatib, head of the National Coalition of Syrian Revolutionary and Opposition Forces.
Earlier, MSC delegates were to discuss the security implications of the eurozone crisis in a panel including German Finance Minister Wolfgang Schaeuble and Lithuanian President Dalia Grybauskaite.
Another debate Friday, on the geopolitical consequences of the US boom in gas production, was to include Deutsche Bank co-chief executive Anshu Jain and EU Energy Commissioner Guenther Oettinger.
Biden on Saturday joins a security discussion with Russian Foreign Minister Sergey Lavrov, NATO Secretary General Anders Fogh Rasmussen and German Foreign Minister Guido Westerwelle.
In Sunday's morning session, Israeli Defence Minister Ehud Barak and French Foreign Minister Laurent Fabius were to make statements on the conflicts in Mali, Syria and beyond.
The MSC forum bills itself as being "dedicated to exchanging new ideas and promoting peaceful conflict resolution, cooperation and dialogue in dealing with today's and future security challenges."