The Trump administration escalated a bitter confrontation with Iran today, demanding that the U.N. Security Council punish the Iranian government for what the U.S. ambassador called its “outlaw behavior” across the Middle East.

“The United States will not turn a blind eye to these violations,” the U.N. ambassador, Nikki Haley, told a Security Council meeting that had been meant to focus on developments in the Israeli-Palestinian conflict.

Haley used her speaking time instead to deliver a critique of Iran. Her remarks were among the most strident denunciations Haley has made of Iran since she became President Donald Trump’s ambassador in January.

The remarks seemed timed partly to respond to international criticism of the administration over Trump’s avowed hostility to the 2015 nuclear agreement between Iran and major powers, including the United States, which he has described as an embarrassment and a disaster.

She spoke less than a week after Trump announced he would disavow the nuclear agreement and might withdraw the United States from the accord altogether unless it was strengthened to his satisfaction.

That decision has deeply angered Iran — which has ruled out any renegotiation — and has raised alarms among many U.S. allies, including Britain, France and Germany, which were among the parties to the agreement.

They have exhorted Congress to preserve the deal, which they say is doing exactly what had been intended — thwarting Iran’s ability to attain a nuclear weapon. They have warned that the United States is risking isolation, loss of credibility and increased global insecurity if the deal unravels.

Accusing the Iranian government of having violated at least four Security Council resolutions with impunity, Haley said that “nearly every threat to peace and security in the Middle East is connected to Iran’s outlaw behavior.”

She argued that the nuclear agreement was an insufficient instrument with which to measure Iran’s relations with the world.

“Iran hides behind its assertion of technical compliance with the nuclear deal while it brazenly violates the other limits on its behavior,” she said. “And we have allowed them to get away with it. This must stop.”

Haley also demanded that the council take action on what she called Iran’s “most threatening act”: ballistic missile launchings.

A Security Council resolution that put the nuclear agreement into effect calls upon Iran to refrain from ballistic missile tests but does not prohibit them. Iran has argued that its missiles are a defensive countermeasure to deter hostile neighbors, notably Israel and Saudi Arabia, both close U.S. allies.

There was no indication that other council members would act on Haley’s demands. China and Russia, veto-wielding members who also are parties to the Iran nuclear agreement, are strong supporters of it.

More broadly, they oppose the Trump administration’s efforts to ostracize Iran.

Iran’s ambassador to the U.N., Gholamali Khoshroo, offered what amounted to a diametrically opposite appraisal of Iran’s behavior in his council remarks, saying “no country has done more than Iran” in fighting Middle East terrorism, most notably in fighting the Islamic State.

“If we had hegemonic ambitions, the nuclear deal would never have been reached,” Khoshroo said. He said Trump’s approach “toward the deal and Iran run counter to all of these efforts and intend to add another crisis to the regional issues.”

Hours earlier in Tehran, Iran’s supreme leader, Ayatollah Ali Khamenei, delivered a tough denunciation of Trump’s position on the nuclear deal and his other criticisms of Iran, calling it “a waste of time to respond to such blatherings and nonsensical remarks by the foulmouthed U.S. president.”

In a speech to academics carried by Iranian state media, Khamenei said Iran would not renounce the nuclear agreement as long as the United States does not. “But if it does,” he said, “we will shred it to bits.”

Trump’s decision announced last Friday not to certify Iran’s compliance with the nuclear agreement triggered a provision in U.S. law that gives Congress 60 days to decide whether to reimpose sanctions that were rescinded under the accord.

Khamenei’s remarks suggested the reimposition of sanctions would be interpreted by Iran as a U.S. withdrawal from the accord. It is unclear whether Congress will take that action.

European leaders, including the European Union’s top foreign policy official, Federica Mogherini, who helped negotiate the nuclear agreement, have urged U.S. lawmakers to preserve it. A growing number of disarmament advocates and diplomats also have publicly defended the agreement.

In the latest indication of support, a group of 25 former foreign ministers said today in a letter to congressional leaders that the agreement was in the best interests of the United States.

The signers included former Secretary of State Madeleine K. Albright of the United States and many of her counterparts from Europe and elsewhere.

“A unilateral withdrawal from the agreement would have far-reaching adverse consequences for the security of the United States and America’s standing in the world,” the letter said.

“We know from experience that the world counts on the United States to live up to its commitments,” it said. “If the United States loses its credibility, the consequences for its security, and the security of its allies, would be disastrous.”

In a telephone interview, Albright said the group of former ministers, which meets a few times a year, considered the nuclear agreement “such a good example of multilateral cooperation” that its members felt it was important to speak out.

Albright, whose first diplomatic post was as the U.S. ambassador to the United Nations, said she understood Haley’s concerns about Iran’s “counterproductive and dangerous” activities.

Still, she said: “Everything would be more serious if they had a nuclear weapon. You’re safer if they don’t have one.”

© 2017 The New York Times Company