Nikki Haley, the United States ambassador to the United Nations, is set to lay out Thursday what the Trump administration claims is "irrefutable evidence that Iran has deliberately violated its international obligations and has tried and failed to cover up these violations," her office said in a statement Wednesday.
The announcement will come as the U.N. presents a report today on the implementation of U.N. Security Council Resolution 2231. That's the resolution that endorsed the Iran nuclear agreement, known formally as the Joint Comprehensive Plan of Action, and calls on Iran not to undertake any activity related to ballistic missiles for eight years as well.
It remains to be seen whether the Trump administration will seek to punish Iran for the alleged "violations," but Haley's announcement comes a month before the Jan. 13 deadline by when President Donald Trump must again certify whether or not Iran is in compliance with the nuclear deal, which was negotiated under the Obama administration, and also decide whether to extend a waiver on sanctions.
On Oct. 13, Trump announced a decision not to certify Iran's compliance, stating, "We will not continue down a path whose predictable conclusion is more violence, more chaos, the very real threat of Iran's nuclear breakout."
"In the event we are not able to reach a solution working with Congress and our allies, then the agreement will be terminated," the president warned at the time. "It is under continuous review, and our participation can be canceled by me, as president, at any time."
Trump's announcement triggered a 60-day period for Congress to decide whether to reimpose sanctions that were lifted under the deal. That period ended Tuesday with Congress deciding not to act.
In the U.N. report -- a regular update on the implementation of UNSCR 2231, marked "confidential" and obtained by ABC News -- Secretary-General Antonio Guterres criticizes the Trump administration because, he writes, it "regrettably created considerable uncertainty regarding the future" of the nuclear agreement with that October announcement.
"I continue to believe that the Plan is the best way to ensure the exclusively peaceful nature of the Islamic Republic of Iran's nuclear programme," he adds. "It is my hope that it will be preserved."
But the report also details several of the incidents that have been raised by various countries, including the United States and Saudi Arabia, regarding Iran's ballistic missile tests and its alleged transfer of missiles and arms.
Haley is expected to build on some of those details and argue that Iran has violated its obligations under the resolution -- although the secretary-general merely summarizes what other countries have reported to the U.N. but generally draws no conclusions. The U.N. is "still analyzing the information provided," he writes repeatedly.
Among the incidents detailed in the report are several missiles fired by Houthi fighters in Yemen -- including one that landed close to Riyadh's international airport on Nov. 4 -- that the U.S. and others allege contain markings that show it came from Iran.
The report also mentions unmanned vehicles, drones and arms allegedly supplied by Iran to the Houthis.
Iran has denied these allegations -- which Haley will look to combat with that "irrefutable evidence" Thursday.