As many as 1,000 elderly villagers in Gambia may have been kidnapped by "witch doctors" who hold people hostage and force them to drink poisonous concoctions, Amnesty International told the BBC.
While the Gambian government has not commented, witnesses claim police and army officials, as well as the president's guards, have helped the "witch doctors" round up alleged witches, the BBC reported.
Amnesty International called on the government of President Yahya Jammeh, who seized power in a 1994 coup and has claimed he can cure AIDS, to halt the campaign and bring those responsible to justice.
Amnesty's U.K. Director Kate Allen told the BBC that hundreds of Gambians have fled to neighboring Senegal to escape the village attacks.
"The Gambian government has to put a stop to this campaign, investigate these attacks immediately and bring those responsible to justice," she said.
Most victims were held for three to five days and all are believed to have been released, Amnesty spokeswoman Eliane Drakopoulos told The Associated Press. But many have been terrorized by the campaign and fear it could spread, she said.
Amnesty said the mixtures have caused people to develop kidney problems, hallucinate, vomit and behave erratically.
The "witch doctors" are reportedly from neighboring Guinea.
The most recent incident, on March 9, took place in a village called Sintet, which was surrounded by paramilitary police armed with guns and shovels before dawn. Amnesty quoted a witness as saying that security forces vowed "that anyone who tries to escape will be buried six feet under."
About 300 men and women were forced at gunpoint into buses that took them to Jammeh's farm at Kanilai.
"Once there, they were stripped and forced to drink 'dirty water' from herbs and were also bathed with these dirty herbs" that caused diarrhea and vomiting, the witness said. "I stayed there for five days ... I cannot believe that this type of treatment is taking place in Gambia. It is from the dark ages."
The Associated Press contributed to this report.