The U.S. Congress has passed a measure that, if signed by the president, would effectively deny a visa to Iran's choice of ambassador to the United Nations.
The House of Representatives passed the bill unanimously on April 10, four days after the Senate did the same.
The measure now goes to President Barack Obama for his signature.
Hamid Abutalebi is accused of participating in the 1979 seizure of the U.S. Embassy in Tehran and the holding of 52 Americans hostage for 444 days.
Abutalebi denies playing any role in the embassy seizure, saying he only served as a translator for the hostage-takers.
On April 8, the Obama administration said Abutalebi's expected nomination was "not viable."
Iran has rejected the U.S. reservations as "unacceptable."
Based on reporting by AP and AFP