“Between 2005 and 2011 around 3,000 people were lynched by frightened neighbours who thought they were witches,” the Legal and Human Rights Centre (LHRC) said in a report.
“On average 500 people… particularly old women with red eyes, are killed every year in Tanzania because they are suspected of being witches,” the report said.
The provinces hardest hit are Mwanza and Shinyanga in the north of the country, LHRC said.
“In Shinyanga province for example 242 people were killed because of local beliefs in witchcraft between January 2010 and January 2011 alone,” it said.
The rights group explained that red eyes are feared as a sign of witchcraft, even if they in fact often result from the use of cow dung as cooking fuel in impoverished communities.
The centre said that many local people believe that witchcraft is behind every misfortune from infertility and poverty to failure in business, famine and earthquakes.