MNA � The United Nations has expressed concern about the US' increasingly confrontational rhetoric with Iran and called for calm.

"We are concerned about the rising rhetoric," said UN spokesman Stephane Dujarric.

"We would ask all parties to lower the rhetoric and lower the threshold of action as well," Dujarric added.

Dujarric's remarks came amid concerns about a potential military conflict between the United States and Iran.

US President Donald Trump's threatened Iran in a tweet made late last week, saying that a fight against the United States would be its "official end."

Iranian Foreign Minister Mohammad Javad Zarif, in response, warned Trump that he should never threaten Iranians, and called on Trump to try "respect" instead of �economic terrorism� and �genocidal taunts".

In a letter to UN Security Council, Iran has warned about the recent alarming security situation in the Persian Gulf region, saying that while it will never choose war as an option, the country is entitled to self-defense.

�Iran will never choose war as an option or strategy in pursuing its foreign policy. But if war is imposed on us, Iran will exercise its inherent right to self-defense in order to defend its nation and to secure its interests,� wrote Iranian Ambassador to UN, Majid Takht-Ravanchi, in a letter to UN Secretary General Antonio Guterres.