On the sidelines of the United Nations General Assembly, African Union (AU) Commission President Moussa Faki Mahamat, European Commission President Jean-Claude Juncker, High Representative of the EU for Foreign Affairs and Security Policy Federica Mogherini and United Nations (UN) Secretary General António Guterres reaffirmed their determination, in New York on Sunday 23 September, to cooperate more closely in order to address global challenges together, notably peace and security.