UNITED NATIONS, NEW YORK: President Donald Trump will return to the United Nations this week seeking greater international cooperation in confronting Iran, even as his administration moves to reshape the global institution hosting world leaders, U.S. Ambassador to the U.N. Mike Waltz told Fox News Digital in an exclusive interview ahead of the gathering.

With the U.S.-Iran war entering its seventh month, Trump is expected to address the General Assembly on Tuesday and meet Gulf leaders whose countries have been directly affected by the conflict.

The gathering comes as Washington seeks to intensify economic pressure on Tehran, European allies confront Russia's ongoing war in Ukraine, and the administration faces questions about whether its push to reduce the U.N.'s size and spending risks diminishing the organization's ability to respond to international crises.

Waltz outlined what Washington expects from its partners on Iran: full enforcement of sanctions against Tehran, with consequences for countries that fail to comply.

"They will reinforce that message, but importantly, it's all of these countries actually enforcing the sanctions and what they're going to hear is there will be consequences for friend and foe," Waltz said. "The president is doing this for the future security of the world."

European and Asian allies have largely resisted Trump's requests for assistance in the Iran conflict, which began with U.S. and Israeli strikes in February, Strait of Hormuz and its Houthi allies tightening their grip on a critical Red Sea shipping corridor.

Waltz said the administration intends to make sanctions enforcement a central part of its diplomatic push during UNGA.

"The Iranian economy continues to crater," Waltz said, pointing to the country's currency, inflation and the U.S. naval blockade. "One way or another, the president has been crystal clear on our goals here that Iran cannot and will not have a nuclear weapon."

His remarks follow abudget reductions, with roughly 3,000 headquarters positions being cut and a reduction of approximately 25% in peacekeeping personnel.

"We have the U.N. on a diet," Waltz said.

But Waltz also made clear that the administration does not intend to abandon the United Nations.

"There's got to be one place in the world where everyone can come together and put diplomacy first and can actually talk," he said. "We don't ever want to see a U.N. in Beijing or Moscow or Brussels."

"If we just walked away, you'd have 192 countries talking without us," Waltz added.

Gaza offers one example of how the administration intends to use the U.N. while limiting direct American military involvement. Waltz pointed to the U.N.-endorsed Board of Peace and the planned International Stabilization Force, which is intended to support security and a postwar transition in Gaza. The ambassador said he does not want American troops deployed there, arguing that international security operations should allow other countries to share the burden. The U.N. Security Council endorsed the Gaza peace plan and authorized the stabilization force in November 2025.

The State Department said Sept. 18 that Secretary of State Marco Rubio will be in New York from Sept. 20–23 to meet foreign counterparts, advance U.S. security and economic priorities and continue the administration's campaign for U.N. reform.

Trump arrives in New York days after announcing a new security agreement with Denmark and Greenland aimed at expanding the American military presence in the Arctic while restricting adversaries from establishing bases or making sensitive investments on the island.

The agreement falls short of Trump's earlier ambition to acquire Greenland, which remains an autonomous territory within the Kingdom of Denmark. Denmark and Greenland have stressed that the arrangement will not compromise the island's sovereignty or right to self-determination. Additional details of the agreement have yet to be made public.

Waltz told Fox News Digital that the deal reflects the Arctic's growing strategic importance as melting ice opens new shipping routes and increases access to energy and mineral resources.

"It's incredibly significant," Waltz said, pointing to Russia's Arctic military capabilities and the potential for new shipping routes to transform global trade.

"It took some tough tweets, maybe some tough language," he said. "We now have an agreement with our ally Denmark."

The agreement comes as European governments confront overlapping security challenges involving Russia's war in Ukraine, Arctic defense and uncertainty over transatlantic security arrangements, while Washington seeks greater allied cooperation in its campaign against Iran.

The U.N. expects 73 heads of state and 45 heads of government, along with 49 ministers, 11 vice presidents and one crown prince, to attend High-Level Week, U.N. spokesperson Stéphane Dujarric told reporters Friday.

Member states have submitted approximately 1,000 requests for bilateral meetings, while about 168 events are scheduled alongside the official proceedings.

The 81st General Assembly's General Debate begins Tuesday and runs through Sept. 28.

Beyond Iran, world leaders are expected to address Russia's invasion of Ukraine, the future of Gaza, international security and the U.N.'s ability to respond to emerging global challenges.

Waltz described the administration's approach with a slogan inspired by the president's political branding: "Make the U.N. great again."

But the immediate diplomatic questions facing Washington are more concrete: whether allies will increase pressure on Iran, whether Gulf leaders can agree on a path toward ending the conflict and whether the administration's push for a leaner U.N. can coexist with its efforts to use the organization to address international security challenges.