There are unconfirmed reports that the Iranian authorities have decided to go ahead with the execution of a pastor.

Pastor Yousef Nadarkhani was sentenced to death for apostasy and has been in prison for several months as he awaits the outcome of his appeal.

According to Christian Solidarity Worldwide, his lawyer is trying to confirm reports that the Iranian authorities have decided to uphold the death sentence.

CSW is concerned that Nadarkahni will be executed at any time without prior notification and that the authorities will merely announce it later, a practice the organisation says is not uncommon in Iran.

The sentence has been condemned by the UK and US governments but Pastor Nadarkhani has won the admiration of the international Christian community because of his refusal on at least four occasions to recant his faith in exchange for freedom.

CSW’s Chief Executive Mervyn Thomas called upon the international community to put pressure on the Iranian government to release Pastor Nadharkani.

"CSW is deeply concerned at the very real possibility that Pastor Nadarkhani’s death sentence could be carried out at any time, despite the fact that there is no legal basis for this sentence," he said.

"We urge the Iranian authorities to follow due process, and ensure respect for the right to freedom of religion.”

He also expressed concern for evangelical church pastor, Farshid Fathi Malayeri, who was detained without charge at the end of 2010 and held for over a year before his trial took place earlier this month.

Mr Thomas said: "We urge the international community to press the Iranian government to release Pastor Nadarkhani, Farshid Fathi Malayeri and others who are unjustly imprisoned or facing execution following flawed judicial processes.

"It is unacceptable that Farshid Fathi Malayeri had to endure over a year of incarceration while awaiting his trial date, including a lengthy time in solitary confinement.

"CSW also remains deeply concerned at the ongoing harassment and imprisonment of Christians, Baha’is and other minorities, actions which contravene international covenants to which Iran is signatory, including the International Covenant on Civil and Political Rights (ICCPR), which guarantees freedom of religion."