German Chancellor Angela Merkel said Thursday she would work towards a political union in Europe with willing partner countries even if that meant a two-speed approach. \"We need more Europe...a budget union...and we we need a political union first and foremost,\" Merkel told German public television. \"We must step by step cede responsibilities to Europe.\" The German leader, who has been criticised for staunch opposition to some proposals to resolve the eurozone debt crisis, added: \"We must not remain immobile because one country or another does not want to follow yet.\" On Wednesday, Merkel discussed the debt crisis with US President Barack Obama and Italian Prime Minister Mario Monti in the latest in a series of calls with global leaders. British Prime Minister David Cameron also called on Europe Wednesday to come up with an \"immediate plan\" to resolve the eurozone crisis. Cameron will meet Merkel for further talks in Germany later Thursday. Leaders are under intense pressure from their populations as well to take action to break the back of the two year old crisis at a June 28-29 summit. But Merkel told German television that not all of the bloc\'s problems could be solved with one summit meeting. The German chancellor said she did not believe \"that one summit is capable of settling everything in one fell swoop.\"