In an urgent letter to the Security Council dated 19 February 2026, the Permanent Mission of the Islamic Republic of Iran spelled out the country’s position amid mounting US threats. The letter, signed by Ambassador Amir Sacid Fravani, emphasizes that Iran remains committed to diplomacy, but will exercise its inherent right to self-defence under Article 51 of the UN Charter if attacked. “In such circumstances, all bases, facilities, and assets of the hostile force in the region would constitute legitimate targets,” the letter states, underscoring Tehran’s readiness for a military confrontation if provoked.
The correspondence comes after repeated US threats, including President Trump’s social media statement on 18 February suggesting that American bases in Diego Garcia and RAF Fairford could be used in a strike against Iran. According to the letter, such threats “constitute a flagrant violation of the Charter of the United Nations and international law” and risk plunging the Middle East into further instability. The Iranian government insists that the buildup of US military equipment and assets in the region signals that these are not empty warnings but a real risk of aggression with potentially catastrophic consequences.
Iran’s letter stresses that it has engaged seriously and constructively in nuclear talks with Washington, with the aim of clarifying ambiguities around its nuclear programme and securing the full lifting of unilateral coercive measures imposed by the United States. Tehran portrays itself as committed to diplomacy, arguing that a mutually acceptable and results-oriented solution is possible if the US also demonstrates sincerity and respects international law. “The achievement of a durable and balanced solution would be entirely possible,” the letter reads.
The Islamic Republic is calling on the UN Security Council and Secretary-General António Guterres to act immediately to prevent escalation. The letter demands that the Council ensure Washington ceases its threats, complies with Article 2(4) of the UN Charter, and refrains from any actions that could provoke military confrontation. Tehran warns that failure to address such unlawful threats risks normalizing aggression as a tool of foreign policy, with consequences that could extend beyond the region.
While Iran insists it does not seek conflict and will not initiate war, the letter makes clear that any attack against its territory would be met with a proportionate and decisive response. Tehran frames this stance as an exercise of its inherent right to self-defence. The letter explicitly places responsibility for any unpredictable or uncontrolled outcomes on the United States, signaling that Tehran intends to hold Washington accountable for any escalation resulting from its military actions.
This warning comes amid heightened tensions following years of strained US-Iran relations. Previous confrontations, including US and Israeli strikes on Iranian nuclear facilities and missile infrastructure, have demonstrated Tehran’s capability to recover and adapt its defence systems. Analysts note that Iran’s extensive missile arsenal, coupled with its network of regional proxies, would make any military engagement with the United States or its allies unpredictable and potentially devastating.
Regional observers say the letter also serves as a signal to Israel, which has coordinated closely with the United States on security matters. Israeli officials have previously expressed willingness to act in conjunction with the US if Iran were perceived to pose an imminent threat. Tehran’s letter makes clear that any such coordination would render US and Israeli bases and assets legitimate targets under Iranian self-defence doctrine.
Experts emphasize the timing of the letter as crucial. With the United States reportedly preparing military options in the Gulf and drawing on bases in Diego Garcia and RAF Fairford, Iran’s message is meant to place legal and political pressure on Washington while rallying international attention to what it calls “unlawful threats.” The Iranian government’s emphasis on international law and the UN Charter highlights its strategy of framing potential US actions as violations of global norms, thereby attempting to constrain unilateral military moves diplomatically.
The letter also reiterates Tehran’s commitment to nuclear non-proliferation while defending its sovereign rights. It cites the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) as a legal framework under which Iran seeks recognition for its peaceful nuclear programme. This dual approach—asserting legal rights while threatening proportionate military retaliation—reflects Iran’s longstanding policy of balancing diplomacy with strategic deterrence.
While Washington has yet to respond formally to the letter, the tone suggests that Tehran is preparing for all eventualities. Analysts warn that any miscalculation could spark a rapid escalation, drawing in not only the US and Israel but also regional allies and proxies. The letter underscores that Iran sees US military threats as a direct challenge to its sovereignty and is prepared to act decisively if necessary.
