Iran told UN Secretary-General Antonio Guterres on Thursday that Tehran will consider bases, facilities, and assets of the "hostile force" in the region as legitimate targets if it faces military aggression.
US President Donald Trump's rhetoric towards Iran "signals a real risk of military aggression," Iran's permanent mission to the United Nations said in the letter, adding that Iran did not want a war.
The letter cited Trump's social media post in which he wrote, "Should Iran decide not to make a deal, it may be necessary for the United States to use Diego Garcia and the Airfield located in Fairford in order to eradicate a potential attack."
Iran prepared to respond 'decisively'
The letter claimed that should the US approach talks with "seriousness and sincerity and demonstrate genuine respect for the principles of the Charter of the United Nations and the peremptory norms of international law," a "durable and balanced solution" could be achieved.
However, if subjected to military aggression, Iran will respond "decisively," the letter said.