NEW YORK (AP) — “I have decided,” President Donald Trump declared Wednesday, announcing he’d reached a verdict on the Iran nuclear deal’s future even before top U.S. and Iranian officials held their highest-level talks of his presidency. Iran’s president, meanwhile, lashed out at “ignorant, absurd and hateful rhetoric” in response to Trump’s blistering attack at the U.N.

The jabbing between Trump and Iran’s Hassan Rouhani set the stage for a contentious meeting of the nuclear accord’s parties. Trump has sent strong signals that he could walk away from the seven-nation agreement, which would potentially lead to new U.S. sanctions on Iran and its international trading partners. The Iranians, in turn, have threatened to respond to any U.S. pullout by restarting nuclear activities that could take them closer to bomb-making capability.

Asked about his stance on the nuclear pact Wednesday, Trump said he had made a decision. Pressed for details, he replied coyly: “I’ll let you know.”

Shortly afterward, Vice President Mike Pence told the U.N. Security Council that Iran “continues to flout the spirit of the Iran deal, destabilizing the region and brazenly threatening the security of sovereign nations,” a toned-down version of the diatribe delivered by Trump in a General Assembly speech to fellow world leaders Tuesday.

It wasn’t clear if Trump had made a final decision to leave or stick with the Iran deal. On several other issues over his presidency, he has teased reporters with the idea that a major verdict might be imminent, only to delay announcements for weeks or months. Trump must next certify by Oct. 15 if Iran is complying with the deal, and officials have said Trump may use that occasion to declare Iran in violation.

In any event, the U.S.-Iranian exchanges augured poorly for Wednesday’s gathering of diplomats including Secretary of State Rex Tillerson and Iranian Foreign Minister Mohammad Javad Zarif. A year ago, such a get-together would have been considered routine as nations strove to implement an agreement that curtailed Iran’s nuclear activity in exchange for an end to various oil, trade and financial restrictions on the country. In the current environment, it is anything but ordinary.

Zarif and his delegation arrived first for the meeting at the U.N. Security Council chamber. He was followed by Tillerson and his top aides, and the two sides spent several minutes apparently alone in the room before others, including E.U. foreign policy chief Federica Mogherini and Russian Foreign Minister Sergey Lavrov, showed up. None of the participants spoke to journalists who were brought in for a brief photo opportunity.

Addressing the General Assembly earlier, Rouhani said his country won’t be the first to violate the nuclear agreement, “but it will respond decisively to its violation by any party.” In a dismissive jab at Trump he said, “It will be a great pity if this agreement were to be destroyed by rogue newcomers to the world of politics.”

“By violating its international commitments, the new U.S. administration only destroys its own credibility and undermines international confidence in negotiating with it or accepting its word or promise,” Rouhani said. That echoes criticism even some of America’s allies have leveled at a time when the United States hopes to draw North Korea into a negotiation over its rapidly expanding nuclear arsenal.

Taking aim more specifically at Trump’s speech on Tuesday, Rouhani said: “The ignorant, absurd and hateful rhetoric filled with ridiculously baseless allegations that was uttered before this august body yesterday was not only unfit to be heard at the United Nations, which was established to promote peace and respect.”

Rouhani then told reporters at a news conference that the Iranian people are waiting for an apology from Trump for his “extremely offensive” rhetoric and baseless allegations. He said Trump is seeking “an excuse” to pull out of the nuclear deal and that it would be a “waste of time” for him to meet the president.

Trump’s withering critique in his own speech included an accusation that Iran’s government “masks a corrupt dictatorship behind the false guise of a democracy,” while ruthlessly repressing its people.

“It has turned a wealthy country with a rich history and culture into an economically depleted rogue state whose chief exports are violence, bloodshed and chaos,” Trump said, repeating a litany of oft-spoken U.S. complaints. These include Iran’s antipathy to Israel, support for terrorism and Syrian President Bashar Assad, ballistic missile testing and its nuclear program.

“We cannot let a murderous regime continue these destabilizing activities while building dangerous missiles,” Trump said. “And we cannot abide by an agreement if it provides cover for the eventual construction of a nuclear program.”

Trump has said repeatedly that he is inclined not to certify Iranian compliance after having twice found the country compliant at earlier deadlines. Denying certification could lead the U.S. to reintroduce sanctions, which in turn could lead Iran to then walk away from the deal or restart some nuclear activities it curtailed two years ago.

The rhetorical threats have worried the other countries who are part of the agreement: Britain, China, France, Germany and Russia. The Europeans, in particular, have expressed their disapproval of Trump’s threats and talked about trying to lobby the U.S. to abide by the accord. If the U.S. tries to activate globally enforceable sanctions on Iran again, European countries could balk, another potential repercussion Trump must weigh.

Iran rejects that it has broken the agreement, and a U.N. report this month pointed to no Iranian violations.

Seven senior Democratic senators on Wednesday wrote a letter to Tillerson, Defense Secretary James Mattis and other Cabinet members seeking details on any Iranian violations.

As for the recertification next month, they wrote, “We are unaware of any information in the interim that would argue for a change in those determinations in October.”