U.N. Secretary General Ban Ki-moon applauds as he declares the 69th session of the United Nations General Assembly open, Sept 24, 2014. [Photo/IC]

UNITED NATIONS - This year's UN General Assembly general debate started at the UN headquarters in New York on Wednesday.

The assembly is the main deliberative organ of the world body. Comprising all 193 members, it provides a unique forum for multilateral discussion of the full spectrum of international issues.

The General Assembly meets in regular session intensively from September to December each year. At the beginning of each regular session, the assembly holds a general debate, often addressed by heads of state and government to express their views on the most pressing international issues.

The general debate usually opens on Tuesday, one week after the opening of the regular session of the assembly.

However, tradition was already broken this year when the debate opening was pushed back a day to Wednesday, Sept 24, to accommodate a UN climate summit.

More than 140 heads of state or government are expected to attend this year's general debate -- one of the highest turnouts in UN history.

Each speaker has 15 minutes at the rostrum.

The theme for this year's general debate is "Delivering on and Implementing a Transformative Post-2015 Development Agenda."