AMNA NAWAZ: Welcome to the "News Hour."

The president of Iran told the United Nations General Assembly his country won't bend to U.S.

intimidation just a day after President Trump threatened to escalate the war from the very same stage.

GEOFF BENNETT: On the sidelines, U.S.

and Iranian officials signaled no major breakthroughs in mediated talks.

Nick Schifrin has the latest after another busy day in New York.

NICK SCHIFRIN: It is a building on U.S.

soil, an organization dedicated to peace, and never before has it hosted the leader of a country at war with its host until today.

MASOUD PEZESHKIAN, Iranian President (through translator): Yesterday, the United States president described us as terrorists.

We have been the victims of terrorism.

NICK SCHIFRIN: And on the same dais where President Trump yesterday delivered this threat... DONALD TRUMP, President of the United States: Or do I annihilate the Islamic Republic, and do it quickly, never giving them a chance to kill and destroy people and countries again?

NICK SCHIFRIN: ... Iranian President Masoud Pezeshkian delivered his own defiance.

MASOUD PEZESHKIAN (through translator): We will never bow our head or bend at the knee.

Iran must be understood by Mr.

Trump and those who seek to bully us that we are ready for dialogue and diplomacy and negotiations without accepting the language of force.

NICK SCHIFRIN: Within minutes, the sole member of the U.S.

delegation had heard enough and walked out of the room.

But, inside Iran, Pezeshkian leads the faction that advocates for negotiation and economic integration with the West.

He's losing that argument to hard-liners, who today threatened Iran's neighbors after they cooperated with U.S.

sanctions banning Iranian airlines.

MOHSEN REZAEI, Secretary of Iranian Supreme National Security Council (through translator): If any country joins the United States in this adventure, its airports will no longer be able to operate flights.

The choice is yours.

MARCO RUBIO, U.S.

Secretary of State: Do they want to be a country or do they want to be a revolution?

NICK SCHIFRIN: Speaking right after Pezeshkian, Secretary of State Marco Rubio called yesterday's indirect talks between Iranian Foreign Minister Abbas Araghchi and American mediators Steve Witkoff and Jared Kushner significant.

But he said Pezeshkian's speech was the pot calling the kettle black.

MARCO RUBIO: Slaughtering 10,000 of your own people in protests is a violation of the U.N.

I hope it's a violation of the U.N.

principles.

I think sponsoring terrorist organizations in the region to attack your neighbors, attack energy infrastructure, attack civilian sites is a violation of the U.N.

system.

So I don't know what standing Iran has to lecture anyone on human rights or the international system when they habitually violate it.

NICK SCHIFRIN: But Rubio acknowledged that another violator of the international system, Russian President Vladimir Putin, is invited to Florida in December, when President Trump hosts the G20 in his Doral resort.

MARCO RUBIO: We think it's an opportunity for him to engage not just with the president, but with other world leaders.

We hope that's an invitation he will accept.

NICK SCHIFRIN: But, today, Kyiv was filled with the sound of Russian drone strikes.

Authorities said at least two people were killed and dozens injured... VOLODYMYR ZELENSKYY, Ukrainian President: De-escalation steps are important, are needed before winter, now.

NICK SCHIFRIN: ... as Ukrainian President Volodymyr Zelenskyy warned the war could escalate.

And as Ukraine begins to rely on autonomous weapons, Zelenskyy warned the AI future could become the present.

VOLODYMYR ZELENSKYY: As early as next year, there is already a real possibility that AI, not only people, will begin -- will begin to decide what happens on the battlefield.

And we need peace before we reach that point.

DARIO AMODEI, CEO and Co-Founder, Anthropic: That AI could be a risk to humanity as a whole.

NICK SCHIFRIN: Today, the Security Council held its first ever U.N.

General Assembly AI meeting, including warnings from American AI leaders.

SAM ALTMAN, CEO, OpenAI: No one person or company or country should be able to use the most powerful AI models to impose their world view on everyone else.

NICK SCHIFRIN: But, in this chamber, the flawed but still only international body whose resolutions are legally binding, it fell to the co-chair of the U.N.

's independent AI panel, Yoshua Bengio, to warn the world it must police AI companies and issue a clarion call for collaboration.

YOSHUA BENGIO, Co-Chair, U.N.

Independent International Panel on AI: Today, a handful of companies and countries are acting in their self-interest by taking reckless risks with humanity's fate.

Our future, all of us, our future is at stake.

Decisions that affect us all should be made by us all.

The choice is still ours, but we must act now to correct the trajectory.

NICK SCHIFRIN: This year's U.N.

General Assembly theme is Restoring Trust, a U.N.

that delivers for all.

This week, that sentiment has been fleeting, as many here are worried the future feels fractured and uncertain.

For the "PBS News Hour," I'm Nick Schifrin.