Christian convert Fatemeh Mary Mohammadi (Twitter/Mary mohammadi)

“There has since been no news of Mary’s safety or whereabouts and her family are said to be very concerned about her,” says the report.

Fatemeh Mohammadi, an Iranian woman who converted to Christianity, was arrested last week in Iran, Benjamin Weinthal of The Jerusalem Post reported, citing non-profit Article 18, a website “dedicated to the protection and promotion of religious freedom in Iran and advocating on behalf of its persecuted Christians.”

The story was first published by the Persian-language news agency HRANA, the site says.

It appears she was arrested, along with a number of other demonstrators, at a protest against the Iranian government following the Ukrainian passenger plane crash that claimed the lives all 176 people aboard. Iran admitted to shooting down the aircraft, claiming it was a “mistake.”

“The 21-year-old, who after her conversion now prefers to be known as Mary, was reportedly arrested on Sunday near Azadi Square, where protests were taking place following the Iranian government’s admission of guilt in the downing of a Ukrainian passenger plane,” reports Article 18.

Mary, whose whereabouts are unknown, had complained on Twitter that Iranians were facing “soft repression,” saying that the government controls the media, the site reports. She included hashtags indicating that “suppression is the norm.”

Combating “soft repression” was harder than “hard repression,” like beatings and tear gas, she continued.

The Iranian regime was “institutionalizing false beliefs through selective coverage of the news,” and “lies that are bigger and more repetitive make them more believable,” Mary said, according to Article 18.

Last year, she was arrested for failing to properly wear a hijab, Article 18 continues. Those charges were since dropped.

Furthermore, the site says, “Mary is a rare example of a Christian activist still living in Iran and she has already spent six months in prison as a result of her Christian activity, which was deemed ‘action against national security’ and ‘propaganda against the system.’”

The activist publicized on social media that at least 10 other converts to Christianity were imprisoned in Iran “as a result of their peaceful religious activities,” Article 18 adds.

”Mary has tweeted about the sentencing of nine converts in Rasht to five years in prison and the one-year sentence given to a 61-year-old fellow woman convert in Karaj, the sister city to Mary’s home city of Tehran,” the freedom-promoting site reports.