Washington: The US called on Iran on Saturday to free seven leaders of the minority Baha'i faith serving 20- year prison sentences, asking Tehran to ensure religious and other freedoms.

The Baha'i leaders were arrested eight years ago and convicted of espionage, insulting religious sanctities and propaganda against the Islamic Republic.

"We join the international community in condemning their continued imprisonment and calling upon the Islamic Republic of Iran to release them immediately, along with all other prisoners of conscience in Iran," State Department spokesman John Kirby said in a statement.

"Furthermore, we call upon Iranian authorities to uphold their own laws and meet their international obligations that guarantee freedom of expression, religion, opinion and assembly for all citizens," he said.

Iran allows religious freedom for several minorities but targets the Baha'i faith, which believes in unity among religions and equality between men and women.

Kirby's statement comes after international sanctions on Iran were lifted as part of its landmark nuclear deal with world powers last year.