Nazeri turned himself in Thursday, a source close to the family told The Associated Press, requesting anonymity out of safety concerns. Nazeri's detention and  Friday's  release were confirmed by Hadi Ghaemi, director of the New York-based International Campaign for Human Rights in Iran.

The singer had been briefly detained at Imam Khomeini Airport in Tehran when he returned to the country on January 4 from a New Year's vacation in Dubai. His passport and identification documents were seized at the time, the source said.

Witnesses at the airport told the source that a crowd of onlookers who had initially sought Nazeri's autograph grew angry that he was being detained and began shouting "Death to the Dictator." Nazeri was allowed to leave the airport, but asked to report to security officials on Thursday.

A hugely popular classical musician in Iran for more than 30 years, Nazeri told The AP in October that he has never faced censorship in Iran - a rarity for any artist. His songs are typically centuries-old Iranian poems set to traditional music.