There's concern over the whereabouts of a Christian woman who was arrested near protests in Iran earlier this month over the shooting down of a Ukrainian passenger jet.

According to local reports, Fatemah Mohammadi, known as Mary, was taken near to Azadi Square in Tehran and friends have received no information about her health or whereabouts.

Her arrest comes just over two years after she was previously imprisoned for six months, having been convicted of membership in evangelical groups, engaging in Christian activities and acting against national security through propagating against the regime.

Religious freedom charity Middle East Concern says she has often been harassed since her release from prison.

In a statement, the charity said: "She was summoned to intelligence offices on 29 September 2018 and harshly interrogated.

"In July 2019, Fatemeh was attacked on a bus by a woman who complained about her improper head scarf. When Fatemeh reported the incident, she was re-arrested and detained. A court hearing in October resulted in Fatemeh being acquitted of having improper hijab (and her assailant was also acquitted of causing bodily harm).

"In December 2019, prior to her sitting an exam, Fatemeh reported that Azad University had suspended her education with no reason given. However, Fatemeh attributes this to her previous convictions and Christian activities."

The charity is encouraging believers to pray for Fatemah and for her release.