The official Iranian News Network (IRIN) announced the executions during its news bulletin, calling the insurgents who were hanged in Sistan-Baluchistan province, "terrorists," and detailing their alleged crimes.
The men were originally scheduled to be hanged in public, but their executions were moved indoors to Zabedan prison, "at the last minute," according to the provincial judiciary chief.
Iran's official news agency, IRNA, reported that the men were accused of a series of crimes, including kidnappings, killings, and bombings for the insurgent group Jundallah.
The brother of the group's leader was also due to be hanged alongside the other men, but his execution was postponed until "later in the week," according to IRNA. Iranian radio had initially announced his hanging, as well.
Those hanged were officially branded "mohareb," or "enemies of God," a charge which carries the death penalty in Iran.
Analysts fear more unrest after hangings
Iran frequently accuses Jundallah, whose name signifies "soldiers of God," of drug-smuggling and terrorism. It also alleges the group is allied with al-Qaida and is supported by the U.S. and Britain.
Advisor on International Terrorism to Britain's House of Commons, Richard Kemp, said Iran frequently charges people with terrorism, without proper evidence and that it likes to accuse the United States and Britain of involvement.
"You have got to question the Iranians' idea of justice and you have got to question what evidence the regime has against these particular individuals. The Iranians have done deals with elements of al-Qaida in the past. When it suits them, they will support al-Qaida's brand of terrorism," said Kemp.
"Obviously, if they are able to prove that the individuals that they have executed are terrorists, then I do not think we should be too unhappy about the way they deal with them, as long as they have gone through a proper judicial process. But the Iranians have a habit of identifying people as terrorists when they are not necessarily terrorists, and they will connect any group like that with America or the British because it is the popular thing to do," he added.Jundallah claimed responsibility for a May bombing inside a Sistan-Baluchistan mosque that left 25 people dead.
The group, which also calls itself the "People's Resistance Movement of Iran," claims to be defending the rights of Baluchis and of Sunni Muslims inside mostly Shi'ite Iran.
Jundallah's leader, Abdolmalik Rigi told al-Arabiya TV in October his group was "fighting to have the same rights of Iranian Shi'ites," and not to be "second-class citizens."