Some 100 world leaders descend on New York next week in a partial return of the annual UN extravaganza despite Covid concerns, with progress sought on pressing global problems -- starting with the pandemic.
Afghanistan, in the shadow of high tension between the United States and China.
"We need to re-establish confidence. The current geopolitical division in the world is an obstacle," Secretary-General Antonio Guterres told AFP ahead of the summit.
The world "is really in a very dangerous situation," he said. "We need to sound an alarm to wake up political leaders."
US President Joe Biden will address the General Assembly for the first time on Tuesday and a day later will convene a virtual summit on Covid-19 as he seeks to show US leadership on vaccines.
With the Delta variant triggering renewed infection spikes, Guterres warned that the world was "heading in the wrong direction in all areas" on the pandemic.
Other world leaders set to attend include Turkish President Recep Tayyip Erdogan and Israeli Prime Minister Naftali Bennett, who like Biden will be making his first appearance.
The United States discouraged heads of state from visiting and asked that delegations be kept small as a way to fight Covid-19. French President Emmanuel Macron, a frequent UN presence, will be among leaders who cited Covid concerns for sending a pre-recorded video.