Up to 1,000 Gambian villagers have been abducted by "witch doctors" to secret detention centres and forced to drink potions, a human rights group says.
Amnesty International said some forced to drink the concoctions developed kidney problems, and two had died.
Officials in the police, army and the president's personal protection guard had accompanied the "witch doctors" in the bizarre roundup, said witnesses.
Gambia's government was unavailable to comment on the claims.
The human rights group asserted that many of those abducted were elderly.
The London-based rights group said the witch hunters, said to be from neighbouring Guinea, were invited into Gambia after the death of the president's aunt earlier this year was blamed on witchcraft.
Kate Allen, Amnesty's UK director, said hundreds of Gambians have fled to neighbouring Senegal for safety after seeing their villages attacked.
"The Gambian government has to put a stop to this campaign, investigate these attacks immediately and bring those responsible to justice," she said.
'Diarrhoea and vomiting'
| Amnesty spoke to villagers who said they had been held for up to five days and forced to drink unknown substances, which they said caused them to hallucinate and behave erratically. The paramilitary police armed with guns and shovels surrounded our village and threatened that anyone who tries to escape will be buried six feet under |
Eyewitnesses and victims told Amnesty the "witch doctors" were from neighbouring Guinea.
As well as police, army and national intelligence agents, they were also reportedly joined by "green boys" - personal protection guards of Gambian President Yahya Jammeh.
Amnesty said the incidents took place in the Foni Kansala district, near to the president's hometown in Kanilai.
In the most recent incident, said to have taken place on 9 March, hundreds of people from Sintet village were allegedly rounded up.
One eyewitness told the rights group: "The paramilitary police armed with guns and shovels surrounded our village and threatened the villagers that anyone who tries to escape will be buried six feet under."
Three hundred men and women were allegedly randomly identified and forced at gunpoint into waiting buses, which ferried them to Kanilai.
Once there, they were stripped and forced to drink dirty herbal water and were bathed with herbs, the eyewitness said.
Many of those who drank the concoctions developed instant diarrhoea and vomiting, the eyewitness added.