US payment of $400 million of Iranian money which sparked outcry among American politicians was followed by another transfer of $1.3 billion, it has been reported.
The total sum of $1.7 billion was related to an arms deal that Iran signed before 1979 when the Shah was a close ally of the United States but Washington was refusing to give it back.
When the news of the Obama administrations $400 million payoff was first broken it set off a firestorm in the United States.
The partisan bickering which followed the payment was so intense that few people asked about what happened to the balance of the Iranian money.
US government officials have now revealed that the remaining $1.3 billion was sent less than two months after Iran received the first installment in cash in January.
"Iran received the balance of $400 million in the Trust Fund as well as roughly $1.3 billion representing a compromise on the interest," US Assistant Secretary of State for Legislative Affairs Julia Frifield has said.
The payment was confirmed by the State Department official to The Weekly Standard, an opinion magazine published by the American mass media behemoth News Corporation reported on Tuesday.
Wooden pallets stacked with euros, Swiss francs and other currencies were flown into Iran in an unmarked cargo plane to cover the first $400 million.
Although the "mechanics" of the second payoff was not confirmed, it was most likely made in cash since the US has no banking relationship with Tehran, The Weekly Standard speculated.
The reason that we had to give them cash is precisely because we are so strict in maintaining sanctions and we dont have a banking relationship with Iran that we couldnt send them a check, President Barack Obama said early this month.
A number of US politicians have accused Obama of paying "ransom" even though the money belonged to Iran.
Both Iranian and US government officials have stressed that the payment was unrelated to the nuclear deal struck with the Islamic Republic in July.
The sum returned to Iran, however, constitutes a fraction of tens of billions of dollars of the Iranian assets which the US has blocked since the Islamic Revolution.
In April, the US Supreme Court ruled that Iran's $2 billion of assets held in an American bank be turned over to families of those killed in a 1983 bombing in Beirut and other attacks which Tehran says have nothing to do with it.
Foreign Minister Mohammad Javad Zarif denounced the seizure as highway robbery and pledged that Iran would retrieve the sum anyway.