Donald Trump is set to call on world leaders to rally together in the face of threats from North Korea and Iran when he addresses the UN General Assembly.
The US president is expected to advocate a concerted global approach to counter nuclear worries emanating from both countries.
Mr Trump, who is making his first appearance at the Assembly in New York, has previously threatened North Korea with "fire and fury", and will argue that dangers posed by Kim Jong-un should unite the world.
It is unclear whether he will criticise particular nations for failing to rein in Pyongyang - notably China.
He will issue warnings over Iran's own nuclear ambitions, while also addressing instability in Venezuela and the fight against terrorism.
In recent weeks, Mr Trump has sharpened his rhetoric towards the North as the stand-off over its weapons programme deepens.
He has repeatedly called on China to exert more influence by cutting ties with the hermit state.
The US leader has spoken of cold-shouldering countries who continue dealing with Pyongyang - a point he is likely to repeat on Tuesday.
Meanwhile, Iran features on a list of countries whose nationals are currently banned from travelling to the US.
The Middle Eastern nation has been accused of fostering terrorism, a point which could feature in Mr Trump's remarks.
During his election campaign, the US leader frequently belittled the UN, meaning his debut speech will be listened to with piqued interest.
On Monday, he previewed his message, styling it "make the United Nations great".
"Such tremendous potential, and I think we'll be able to do this," he said.
In brief remarks to the UN, Mr Trump chastised the world body's bloated bureaucracy and budget, saying, "We are not seeing the results in line with this investment."
But he pledged that the US would be "partners in your work" to make the organisation a more effective force for world peace.