Iran on Thursday warned that US bases, facilities and assets would be "legitimate targets" if the United States follows through on its military threats and attacks.
Amir Saeid Iravani, the Iranian ambassador to the United Nations, made the remarks in a letter to UN Secretary-General Antonio Guterres and the president of the Security Council, which was seen by AFP.
Trump has repeatedly threatened military action against Iran, citing a deadly crackdown on anti-government protesters last month, and then more recently over its nuclear program.
On Thursday, Trump said that Iran had at most 15 days to make a deal and again suggested that the United States would attack if it failed to do so.
His comments followed talks on Tuesday in Geneva between US envoys Steve Witkoff and the president's son-in-law, Jared Kushner, who met indirectly with Iran's top diplomat, who said that there was progress.