The protests around Ashura were Iran's deadliest clashes since protests broke out last summer after incumbent President Mahmoud Ahmadinejad claimed more than 62 percent of the vote in national elections.

At least seven people were killed and hundreds were arrested on Ashura, witnesses said. The Iranian government has denied that its security forces killed anyone, blaming reformists for the violence.

Doulatabadi, the Tehran prosecutor, said Sunday that the judiciary and police forces will be on high alert near the Iranian new year. The judiciary and police will "confront those who disturb the norms of society with high explosives," he said.

The five prisoners were released Sunday from Tehran's Evin prison. ILNA did not release the professional affiliations of the journalists, but they were listed on opposition Web sites.

According to some main opposition Web sites, Tajik is an editor for Farheekhtegan, a weekly magazine, and a freelance journalist.

Shamsolvaezin has edited many of post-revolutionary Iran's first independent newspapers, including Kayhan, Jame'eh, Neshat and Asr-e Azadegan, according to opposition sites. Many of those have been closed down.

Tonkaboni is the editor of the magazine Farhang va Ahang, or Culture and Music, according to opposition sites.

Javad Mozafar is publishing director of Kavir, a publishing house, and vice president of the Committee for the Defense of Prisoners' Rights, according to opposition sites.

Sadegh Rabbani is a retired science professor at the University of Tehran, according to opposition sites.