Canadian Prime Minister Justin Trudeau speaks at the Atlantic Council Global Citizen Awards Gala dinner at the Intrepid Sea, Air & Space Museum in New York City, Tuesday September 19, 2017. THE CANADIAN PRESS/Adrian Wyld

NEW YORK - Donald Trump's first speech at the United Nations trashed the leaders of Iran, Cuba, Syria and Venezuela but reserved special opprobrium for North Korea, dubbing its leader "Rocket Man" and threatening to "totally destroy" the country.

Tuesday's speech was notable more for Trump's high-level trash-talking than for the identity of his targets, given that all have been condemned by previous U.S. presidents. Few others, however, would have used the world's premier international stage to bestow a nickname like the one Trump levelled at Kim Jong Un.

"Rocket Man is on a suicide mission for himself and for his regime," the U.S. president told the UN General Assembly hall.

"No nation on Earth has an interest in seeing this band of criminals arm itself with nuclear weapons and missiles. The United States has great strength and patience, but if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea...

"The United States is ready, willing and able. But hopefully, this will not be necessary. That's what the United Nations is all about. That's what the United Nations is for. Let's see how they do."

He actually thanked the UN for its work in levelling economic sanctions on North Korea, and saluted the role played by China and Russia. Then he went on to attack the regime in Iran ("corrupt," "murderous," exporter of "violence, bloodshed and chaos"), Cuba's Castro government ("corrupt, destabilizing") and Venezuela ("corrupt" purveyors of a failed socialist ideology).

Prior to Trump's speech, the secretary general of the UN, Antonio Guterres, had urged all parties to tone down the rhetoric in the nuclear standoff: "When tensions rise, so does the chance of miscalculation. Fiery talk can lead to fatal misunderstandings... This is a time for statesmanship. We must not sleepwalk our way into war."

Prime Minister Justin Trudeau, who was scheduled to deliver his UN address Thursday, happened to be holding a news conference in Ottawa while Trump was speaking.

"I look forward to seeing his speech myself," he said when asked about the threat against North Korea. He said he shared the world's concern about North Korea's reckless behaviour, and that the best solution would be working with global partners like China, Japan, South Korea and the United States.

Trudeau was asked whether it's time to reconsider participating in the U.S. missile shield, a program Canada refused to join under Paul Martin's Liberal government. The Canadian position has not changed, he said.

The prime minister arrived in New York on Tuesday night to be honoured by the Atlantic Council think tank for his support for international trade and diversity. He was to be introduced by Jordan's Queen Rania, and planned a speech with two themes: defending international institutions, and arguing that people-first policies like labour rights were key to preserving public support for free trade.

"We need to do a better job of ensuring the benefits of trade extend to the middle class and those working hard to join the middle class — not just the wealthiest few," Trudeau said.

The U.S. president's speech tacked in another direction.

Trump's address included some of the nationalist, "America First" themes of his presidency. He began the speech by extolling the virtues of the nation-state, and urged a non-interventionist mentality.

He complained that the U.S. pays 22 per cent of the UN's budget, which he called unfair, but he added: "If (the UN) could actually accomplish all of its stated goals, especially the goal of peace, this investment would easily be well worth it."

He also made cryptic comments about the Iran nuclear deal.

A presidential decision on whether to keep the U.S. in the agreement that dropped some sanctions in exchange for nuclear non-proliferation is forthcoming; Trump slammed the deal, calling it a one-sided embarrassment to the U.S.

He added, cryptically: "I don't think you've heard the last of it, believe me."

Iran is urging him to leave the deal alone — and appears to be linking the issue to North Korea. Iranian President Hassan Rouhani pressed his case that if the deal gets cancelled, other countries will give up on diplomacy with the U.S.

"No one would trust America again," Rouhani told NBC News. "There is no higher price to be paid than this. Because after such a scenario, which country would be willing to sit across the table from the United States?"

Israel's Benjamin Netanyahu, a vocal critic of the Iran agreement, had a decidedly different reaction to Trump.

"In over 30 years in my experience with the UN, I never heard a bolder or more courageous speech," he said on Twitter.

News from © The Canadian Press, 2017