These pictures offer a rare glimpse into the lives and religious practices of the Mandaean community in Iran.
As followers of John the Baptist, members of this small faith group, numbering between 5,000 and 10,000 in Iran, immerse themselves in moving water every Sunday. Because the rituals of birth, baptism, marriage and death centre on water, the Mandaeans have from time immemorial lived close to rivers - the Karoun in Khuzestan province of southwest Iran, and the Tigris and Euphrates in Iraq.
Muslims count the Mandaeans, also known as Sabians, as "people of the book" like themselves, the Christians and the Jews, and Shia clerics do not see them as a threat as they never seek new converts. Yet the community in Iran is disadvantaged because unlike other minority faiths, it is not mentioned in the constitution and has no representative in parliament.
Their refusal to sanction marriage to outsiders has meant the Mandaeans are a shrinking population. In recent years, though, emigration from Iran and especially Iraq has slashed their numbers in the Middle East.
Hasan Sarbakhshian is an Iranian photographer who worked for Associated Press for almost a decade. He has recently left Tehran for Washington DC.