Iran is pushing back against U.S. efforts to strengthen sanctions against Tehran in response to an alleged plot to assassinate the Saudi ambassador to Washington, demanding a public apology and unspecified monetary damages.

The Iranian demands were contained in a recent letter to the U.S., according to an Iranian diplomat, who spoke on condition of anonymity. It calls on the U.S. to apologize publicly to both the Islamic republic and officials of the Al Quds Force for “material and moral damages” caused by “this baseless accusation,” which it argues violated "international rules and regulations."

The letter states that such deception has become "a permanent part of statecraft in the U.S.," according to the source, citing as an example the U.S. invasion of Iraq, which it says was “based on such false information.”

"After killing hundreds of thousands of innocent Iraqis and U.S. soldiers and wasting billions of dollars from the U.S. citizens' pocket, the U.S. has no other way out except leaving Iraq," the diplomatic source said, recounting the argument made in the letter, NBC News reported.