Iran has asked United Nations Secretary-General Ban Ki-moon to convince the United States to stop violating state immunity.
This comes after the top US court ruled that US$2 billion in frozen Iranian assets must be paid to American victims of attacks blamed on Tehran.
Iran's Foreign Minister Javid Zarif wrote to Mr Ban a week after the US Supreme Court ruling, calling on him to use his "good offices in order to induce the US government to adhere to its international obligations".
Mr Zarif's appeal comes amid increasing Iranian frustration at what they say is the failure of the United States to keep its promises regarding sanctions relief agreed under an historic nuclear deal struck last year by Tehran and six world powers.
In the letter, released by the Iranian UN mission, Mr Zarif asked Mr Ban to help secure the release of frozen Iranian assets in US banks and persuade Washington to stop interfering with Iran's international commercial and financial transactions.
"The US Executive branch illegally freezes Iranian national assets; the US Legislative branch legislates to pave the ground for their illicit seizures; and the US Judicial branch issues rulings to confiscate Iranian assets without any base in law or fact," Mr Zarif said.
Mr Ban's spokesman and the US mission to the United Nations did not immediately respond to requests for comment on the letter or the accusations made against the United States.
The US Supreme Court found that the US Congress did not usurp the authority of American courts by passing a 2012 law stating that Iran's frozen funds should go toward satisfying a US$2.65 billion judgment won by the US families against Iran in US federal court in 2007.
"It is in fact the United States that must pay long overdue reparations to the Iranian people for its persistent hostile policies," Mr Zarif wrote, citing incidents including the shooting of an Iranian civil airliner in 1988.