He referred to North Korean leader Kim Jung Un as "Rocket Man", saying he was on a "suicide mission" and that he headed a "depraved regime".
This is Trump's first appearance at the General Assembly where he addressed threats from Iran and North Korea among other global concerns.
Despite the forceful rhetoric, Mr Trump told world leaders the United States does not seek to impose its will on other countries and will respect the sovereignty of other nations.
And he scolded nations that he said have enabled and traded with North Korea, seeming to slight China, though he did not mention it by name. But he said the world faces some grave threats that require a collective response from the worldwide community. Then two or three sentences later, he is trashing and vowing to tear up a deal that the United Nations is implementing to prevent Iran from getting access to a nuclear weapon.
"We do not expect diverse countries to share the same cultures, traditions or even systems of government, but we do expect all nations to uphold these two core sovereign duties: to respect the interests of their own people and the rights of every other sovereign nation", he said. Trump has always based his argument for American sovereignty around one thing: transactionalism, or in his kind of language, good deals.
"Authoritarian powers seek to collapse the values the system and alliance that prevented conflicted and tilted the world toward freedom since WWII, says Mr. Trump of the treats posed to the worldwide body".
But the rest of Trump's speech belied that sentiment.
Trump told reporters in August that "North Korea best not make any more threats to the United States".
Trump - who has sought to limit both legal and illegal immigration into the US, called for building a wall on the US-Mexico border and limited the admission of refugees into the US - addressed immigration more explicitly as well.More news: Trump campaign adviser was wiretapped under secret court orders
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Give Trump credit for bringing his authentic self to the United Nations, at the very least.
At the top of the USA agenda is a showdown with Pyongyang. "All responsible leaders have an obligation to serve their own nations".
Trump said the United States is "ready, willing, and able" but still hopes that military option will not become necessary. "But we can no longer be taken advantage of or enter into a one-sided deal where the United States gets nothing in return".
"I will always put American first". At the conclusion of the president's remarks, there was "fuller, polite applause, though not rousing or enthusiastic".
His lashing was a vigorous restatement of what's been said by US leaders before, but was likely to hit home harder for being intensely delivered in diplomatic prime time at the U.N. General Assembly.
Trump's prepared remarks for his speech in Saudi Arabia called for him to say "Islamist extremism" instead - a phrase used to distinguish between the religion of more than a billion people around the world and the fundamentalist political ideology that drives terrorist groups like ISIS and al Qaeda.
The president's comments also reverberated back in Washington, where critics took aim at his warnings to Pyongyang.
Just one day earlier, Trump had given remarks at the United Nations that seemed to signify a softer, more conciliatory tone.
"Major portions of the world are in conflict, and some in fact are going to hell, but the powerful people in this room, under the guidance and auspices of the United Nations, can solve many of these vicious and complex problems", he said.