Iran has told the United Nations secretary-general that it will respond decisively to any military attack against it, warning that all bases and assets of what it calls “the hostile force” in the region would be considered legitimate targets.

In a letter addressed to UN secretary-general Antonio Guterres and the presidency of the UN Security Council, Iran’s permanent mission to the UN said the country neither seeks tension nor conflict. “The Islamic Republic of Iran has repeatedly stated at the highest level that it neither seeks tension nor war and will not initiate any war,” the letter read. It went on to warn, however, that in the event that it is subjected to military aggression, Iran will respond decisively and proportionately in the exercise of its inherent right of self-defense under Article 51 of the Charter of the United Nations.Iran described the US threats as signaling 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. Calling for immediate intervention, the letter urged that the Security Council and the secretary-general must act without delay, before it is too late. Despite the sharp warning, Iran reaffirmed its commitment to diplomacy, saying it has engaged constructively and in good faith in nuclear talks with the United States.

The backdrop to Iran’s warning is a substantial US military presence across the region. The United States currently has between 40,000 and 50,000 troops stationed across West Asia, spread across at least 19 sites in countries including Qatar, Bahrain, Kuwait, the UAE, and Saudi Arabia. That presence has grown sharply in recent weeks, with additional carrier strike groups and air and naval forces deployed amid rising tensions with Tehran. Washington says the buildup is aimed at deterring instability, but Iran has called it provocative and a threat to regional peace.