What to know as world leaders converge at the United Nations this week

World leaders are gathering at the United Nations headquarters in New York this week "in an era of deep uncertainty," says U.N. Secretary-General António Guterres.

This is Guterres' final General Assembly high-level week, as his term ends at the end of the year.

He'll give opening remarks to start the event Tuesday morning, followed by Brazilian President Luiz Inácio Lula da Silva — as Brazil speaks first by tradition — and then President Trump. The packed schedule of other leaders and top officials runs through Sept. 28.

Guterres told reporters last week that he will use his meetings with world leaders to push for de-escalation in the Middle East and freedom of navigation through the Strait of Hormuz and the Bab el-Mandeb waterway. He's also pushing for a ceasefire in Ukraine, well into the fifth year of Russia's full-scale invasion.