According to a story by Morning Star News, human rights group Christian Solidarity Worldwide (CSW) reported that the eight members of the Church of Iran were sentenced in Shiraz, 571 miles south of Tehran.
Seven of them were originally arrested in Oct. 2012, when security forces raided an evening prayer service. The eighth, Massoud Rezaid, was arrested six days later.
Sentences ranged between one and six years.
Morning Star News said Iranian Christian leaders denied the eight were involved in politically subversive activity.
"In accordance with the gospel, the church is apolitical," said a statement released by the National Council of the Church of Iran.
"While individual Christians are entitled to hold political opinions, the church does not. These charges are entirely without foundation.
"However, as loyal citizens we will continue to pray for our leaders and for peace and reconciliation in our nation."
Morning Star News said after their initial arrest, the Christians were detained at Plaque 100, the Iranian Intelligence Ministry's detention center notorious for harsh conditions. They were released after paying enormous bail amounts.
The convicted Christians are expected to appeal their convictions.
Morning Star News said the sentencing comes a month after the presidential election of Hassan Rouhani. Many international analysts believed he would be a modernising force after the eight-year presidency of hardliner Mahmoud Ahmadinejad and his crack-down on religious minorities and political dissidents.
Little has changed in terms of religious freedoms for non-Muslims since Rouhani's election, CSW Press Officer Kiri Kankhwende told Morning Star News.
"It is now common practice to subject religious minorities to political charges, as any alternative belief system is deemed a threat to the theocratic state," she said.
Morning Star News said the sentencing of the eight follows enormous bail amounts imposed by a previous judge, causing severe financial hardships to family and church members. To pay these bills, many used their homes as collateral.
The bail amounts ranged between $80,000 and $200,000, creating hardship for those who assisted in raising the money. The high price was intentionally designed financially punish Christians, according to CSW.
Morning Star News said Iran is a signatory to the International Covenant on Civil and Political Rights, which upholds the rights of all religious minorities to freedom of belief.
But its national law characterises most forms of evangelistic non-Muslim religious activity as national security crimes.
Mervyn Thomas, CSW chief executive, called for the group's unconditional release and for Rouhani to bring Iran's laws into conformity with international standards of religious freedom.
"It is both disappointing and deplorable that the Iranian regime persists in detaining religious minorities on political charges, as ha s occurred once again in this case," Morning Star News reported he said in a news release. "These Christians in no way constitute a threat to the state."
Trial in Tehran
Morning Star News said the sentencing follows the trial of Mostafa Bordbar, 27, another convert to Christianity from Islam. He is charged with participating in an "illegal gathering and participating in a house church", according to Mohabat News.
He could receive between two and 10 years in prison if convicted, his attorney reportedly said.
Before his most recent hearing, on June 9 at Branch 26 of the Revolutionary Court of Tehran, he had a short visit with his parents and fiancé, but not even his lawyer was allowed to enter the courtroom, Mohabat News reported.
Morning Star News said Bordbar is held in Evin Prison, a facility that houses political prisoners alongside the nation's most dangerous criminals.
Morning Star News said his arrest came December 27, 2012, when police raided a Christmas and New Year's celebration in a local Christian's home. He was also detained five years earlier for converting to Christianity and being involved in a house church.
Bordbar was later released on bail.
Judge Pir-Abbas is handling the case. He is known in the international legal arena as the "hanging judge", for handing down long prison sentences and death penalties following 2009 protests of the presidential election.
Mornign Star News said it was Pir-Abbas who sentenced US-Iranian pastor Saeed Abedini, 33, to eight years in Evin Prison on Jan. 27.
According to Mohabat News, Bordbar and two other imprisoned Iranian Christians, Farshid Fathi and Alizreza Seyyedian, wrote a letter to incoming President Rouhani, requesting that he reform the Islamic state's law and ease their suffering.
"When you take control of this respectful position, we hope that with God's help, respect and honour will return to the name of Iran and freedom will be given back to religious minorities, especially Christians, " they wrote.