Iran's envoy to the United Nations has condemned Donald Trump’s threat to use force against the Islamic Republic, warning that any act of aggression will have severe consequences for which the US will bear full responsibility.

"The Islamic Republic of Iran firmly rejects and condemns this reckless threat," Iran's permanent ambassador to the UN Amir-Saeid Iravani said in a Tuesday letter to the UN Security Council.

In his letter, he cited Trump's interviews with The New York Post, in which he said he would prefer a deal with Iran to "bombing the hell out of it."

Trump also told Fox News "there are two ways to stop Tehran from developing a nuclear weapon: ‘With bombs or with a written piece of paper’."

In his letter to the Security Council, Iravani said, "The UN Security Council must not remain silent in the face of such brazen rhetoric, as normalizing the threat to use force sets a dangerous precedent and must be unequivocally condemned."

He warned that "any act of aggression will have severe consequences, for which the US will bear full responsibility."

"As a responsible member of the United Nations, committed to upholding peace, security, and international cooperation, Iran will resolutely defend its sovereignty, territorial integrity, and national interests against any hostile action."