Ukraine's president is expected to face off with Russia's Vladimir Putin's top diplomat on Thursday.
It comes after he urged the United Nations not to grow weary of supporting his country at war.
Volodymyr Zelensky is on a fundraising and morale-raising visit that will also take him to the White House.
Nineteen months after his country was besieged by war, Zelensky returned to the United States to 'remind' the world.
"Evil cannot be trusted!" He said.
"Evil", he told United Nations leaders, that could arrive on their own doorsteps if Putin isn't stopped.
"The goal of the present war against Ukraine is to turn our lands, our people, our lives, our resources into a weapon against you," said Zelensky.
He sought to evoke emotion - mentioning one of the war's most haunting weapons - Ukraine's lost children.
"We know the names of tens of thousands of children and have evidence of hundreds of thousands of others kidnapped by Russia," Zelensky said.
"What will happen to them?"
The Russian representative who attended seemed uninterested, busy playing on his phone.
Nine months after a visit to the White House, Zelensky has arrived at the United Nations in New York City at a time when US lawmakers are increasingly divided over whether to continue pouring money into the Ukrainian war effort.
"Where is the accountability on the money we have already spent? What is the plan for victory? I think that's what the American public wants to know," said House Speaker Kevin McCarthy, a Republican.
Zelensky can count on the support though from the man whom he needs it the most, the US President Joe Biden, who spoke on Wednesday too.
"If we allow Ukraine to be carved up today, is the independence of any nation secure? I'd respectfully suggest the answer's no," Biden said.
And Zelensky's visit to the US isn't over yet.
Later this week, he'll head to Washington to visit the White House again, and then to Congress to convince lawmakers that US funding is money well spent.
But first, he'll be part of a UN Security Council meeting on Thursday.
That might involve coming face-to-face with Putin's Foreign Minister, Sergey Lavrov.
It'll be a good chance to eyeball the enemy.
