Christian Solidarity Worldwide says it is deeply concerned by reports that two Iranian pastors have been charged with apostasy, with one currently facing a death sentence.
Their cases come at a time when religious minorities in the country are experiencing an increase in persecution, including detention and imprisonment.
Seven Baha'i leaders are among those incarcerated for their beliefs.
The Rev Yousef Nadarkhani, from Rasht in Northern Iran, is currently being held incommunicado in Lakan prison, reports CSW, a Christian human rights campaign.
The minister was arrested on 13 October 2009 and charged with apostasy after he questioned the Muslim monopoly on the religious instruction of children in Iran, which contravenes a provision in the Iranian constitution that permits parents to raise children in their own faith. It also violates international statutes to which Iran is party, including the Convention on the Rights of the Child (CRC).
Nadarkhani was reportedly tried and informed orally in late September that he was to receive the death penalty, although the written sentence was not issued until 13 November. The Christian leader's lawyers filed an appeal on 5 December 2010, but a date for the hearing has yet to be announced.
Another minister, the Rev Behrouz Sadegh-Khanjani, a second generation Christian from Tehran and chair of the Pastoral Council of the Church of Iran, has been detained in a high security prison in Shiraz since June this year.
Mr Khanjani was initially arrested in January 2010 after being summoned to Shiraz to offer an explanation for church activities, and was detained along with two other Christians. He was released on bail on 17 March, then was once more summoned to Shiraz on 16 June to “present his defence”, but was re-arrested and transferred to the infamous Plate 100 Prison.
Mr Khanjani has now been charged with apostasy, blasphemy, and "contact with the enemy". The possible penalty is a death sentence. He too is held incommunicado, and despite the gravity of the charges, he has only been given access to his attorney once in the period between his arrest and late November.
For the majority of his imprisonment, Khandjani has been kept in solitary confinement, and CSW says it has received reports that his health is suffering due to extremely unhygienic conditions and mistreatment.
Christian Solidarity Worldwide’s Advocacy Director Andrew Johnston, commented “We are deeply concerned for the welfare of pastors Nadarkhani and Khanjani, who are detained in appalling conditions and cannot be contacted. They are being held solely for exercising their right to freedom of thought, conscience and belief."
"The international community must continue to urge the Iranian Government to release all those detained on the basis of their religious affiliation, to adhere to its obligations under the International Covenant on Civil and Political Rights and the CRC, and to ensure that all of its citizens can fully exercise their right to freedom of religion or belief,” Johnston declared.
More on CSW: www.csw.org.uk/