Baden, Germany, April 03, SPA --The NATO summit celebrating the alliance's 60th birthday opened today evening in the German resort of Baden-Baden as heads of state and government of the 28 member nations gathered for a concert and dinner, dpa reported. The main issues to be tackled at the summit are expected to be the conflict in Afghanistan, relations with Russia and the role of NATO in a changing world. This is the first-ever NATO summit to be co-hosted by two countries, with events also taking place in another German city, Kehl and the French city of Strasbourg. It is also the first summit at which US President Barack Obama is taking part.