President Trump will meet with United Nations Security Council diplomats on Monday as part of an effort to rally an international coalition against Iran.

The meeting, which will be Trump’s second working lunch with the Security Council, comes in the middle of a two-track effort in Congress and with European allies to address flaws that the Trump administration perceives in the nuclear deal negotiated by former President Barack Obama’s team. It’s one stop on a trip that Ambassador Nikki Haley arranged to highlight Iran’s role in conflicts around the Middle East.

Haley will lead the Security Council diplomats in an inspection of debris from a ballistic missile fired from Yemen into Saudi Arabia, according to the U.S. mission, as well as a tour of the Holocaust Museum’s exhibit on the war in Syria. U.S. officials declassified the wreckage to make the case that Iran is arming Houthi rebels in the Yemeni civil war.

“The Iranians are not supposed to be exporting any missiles or any related material,” Haley told reporters. “You will look at all of these weapons and there are markings all over it that show without a doubt these are Iranian-made, these are Iranian-sent, and these are Iranian-given.”

That argument received a boost from United Nations investigators who agreed that the weapons came from Iran. “The United Nations panel’s report did not say Iran had supplied missiles to the Houthis,” the New York Times noted. “But by failing to keep such weapons out of Yemen, the report said, ‘the Islamic Republic of Iran is in noncompliance’ with Resolution 2216, adopted nearly three years ago after the war between the Houthi rebels and the Saudi-backed government in Yemen had begun."

A rollback of Iran’s ballistic missile program is a key priority for Trump’s administration, as the president has threatened to scrap the nuclear deal if lawmakers and allies fail to develop a plan for curbing the regime’s behavior.

“In the absence of such an agreement, the United States will not again waive sanctions in order to stay in the Iran nuclear deal,” Trump said in a Jan. 12 statement. “And if at any time I judge that such an agreement is not within reach, I will withdraw from the deal immediately.”