Three Iranian Christians have been sentenced to five years in prison for "engaging in propaganda against the Islamic regime."

Amin Khaki, Milad Goudarzi and Alireza Nourmohammadi were sentenced by the Revolutionary Court in Karaj, northern Iran.

All three are planning to appeal the verdict, Christian Solidarity Worldwide (CSW) reports. 

The men were charged under a new amendment to the Iranian penal code that criminalizes "sectarian activities". 

It adds that "any deviant education or propaganda that contradicts or interferes with the sacred Islamic shari'a, will be severely punished."

Until the introduction of the amendment earlier this year, Christians were targeted with national security laws.

CSW reports that the three men suffered the additional injustice of being made to stand trial without the presence of a lawyer. 

The court said this was because their lawyer had failed to register in time, but CSW says he met the necessary requirements for participation 10 days before the start of the trial. 

CSW's Founder President Mervyn Thomas said the men should be acquitted.

"The campaign of harassment against Iranian Christians is unrelenting, as these baseless charges against these three men, under a new clause in the penal code, demonstrate," he said.

"CSW calls for the acquittal of these innocent men. We also reiterate our call for the repeal of laws and articles formulated or utilised to target minority communities.

"Finally, we urge the Iranian authorities to release all prisoners detained on account of their religion or belief, and to end the relentless campaign of harassment of Christians and other religious minorities through the judicial system."