Iran’s permanent mission to the United Nations issued a formal warning on Thursday, February 19, 2026, stating that Tehran will respond “decisively and proportionately” to any military aggression, holding the United States “fully and directly responsible” for any resulting consequences.
In a letter addressed to UN Secretary-General António Guterres and the current presidency of the UN Security Council (held by Guyana in February 2026), the mission emphasized that Iran “neither seeks tension nor war and will not initiate any war.” However, it affirmed its readiness to exercise its “inherent right of self-defense under Article 51 of the Charter of the United Nations” if subjected to military attack.
The letter, obtained by Anadolu Agency, explicitly cautioned that “all bases, facilities, and assets of the hostile force in the region would constitute legitimate targets in the context of Iran’s defensive response.” It singled out the United States as bearing “full and direct responsibility for any unpredictable and uncontrolled consequences” that may follow.
The communication cited a February 18, 2026, social media post by U.S. President Donald Trump as “an explicit public threat of the use of force” against Iran. The mission referenced Trump’s mention of potential military action involving U.S. facilities at Diego Garcia (British Indian Ocean Territory) and RAF Fairford in England, interpreting the statement as a credible signal of imminent aggression.
Iran urged the UN Security Council and Secretary-General Guterres to “act without delay, before it is too late,” describing U.S. threats as creating “a real risk of military aggression, the consequences of which would be catastrophic for the region and would constitute a grave threat to international peace and security.”
Despite the strong language, the mission reaffirmed Iran’s commitment to diplomacy, stating that Tehran has engaged “constructively, with seriousness and in good faith” in ongoing indirect nuclear talks with the United States. It reiterated that Iran “is fully committed to the purposes and principles of the Charter of the United Nations and to diplomatic solutions.”
The letter arrives amid heightened tensions following the second round of indirect U.S.-Iran nuclear negotiations in Geneva on February 17, 2026. While both sides described those talks as “constructive” and reported agreement on “guiding principles” for future drafts, Vice President JD Vance and other U.S. officials have stressed that Iran has not yet addressed several of President Trump’s “red lines.” Trump himself has repeatedly warned that failure to reach a meaningful deal could lead to “bad things” for Iran.
The United States has significantly bolstered its military presence in the Middle East in recent weeks, deploying the USS Abraham Lincoln carrier strike group and signaling plans to send the USS Gerald R. Ford. These movements have been accompanied by public statements from U.S. officials emphasizing readiness for military options if diplomacy fails.
Iran has responded with large-scale naval exercises in the Strait of Hormuz (involving Russia and China), temporary closures of parts of the strait for live-fire drills, and repeated warnings that any attack on its territory or nuclear facilities would trigger a broad defensive response across the region.
The UN letter follows a pattern of Iranian diplomatic communications to the Security Council during periods of elevated tension, invoking Article 51 (self-defense) and Article 35 (threats to peace) of the UN Charter to place responsibility on the Council and the Secretary-General to prevent escalation.
No immediate formal response has been issued by the UN Security Council presidency or the Secretary-General’s office as of Thursday evening. However, diplomats note that such letters are typically circulated as official documents (S/2026/...) and placed on the Council’s agenda if requested.
The exchange underscores the fragile state of U.S.-Iran diplomacy at a time when indirect talks continue under Omani mediation while military posturing intensifies on both sides. Analysts warn that miscalculation or escalation in the Persian Gulf could have severe consequences for global energy markets, regional stability, and international peace and security.
Iran maintains that its nuclear program is peaceful and that any agreement must focus on sanctions relief, while the United States insists on strict limits on enrichment, robust verification, and verifiable non-proliferation commitments.
As the Board of Peace—President Trump’s $10 billion private peace initiative—holds its inaugural meeting in Washington, the Iranian letter serves as a stark reminder of the high stakes surrounding nuclear negotiations and the risk of military confrontation in the Middle East.
