GENEVA — Spurred by the killing this week of a young woman accused of witchcraft in Papua New Guinea, the United Nations on Friday called on the country to address increasing vigilante violence against people accused of sorcery and to revoke a controversial sorcery law.

The United Nations human rights office in Geneva said it was deeply disturbed by the killing of the woman, Kepari Leniata, 20, who was stripped, tortured, doused in gasoline and set on fire on Wednesday as hundreds of spectators watched.

The killing in Mount Hagen, the Western Highlands provincial capital, reportedly was carried out by relatives of a 6-year-old boy who, they claimed, had been killed by her sorcery. The crowd blocked police officers and firefighters who tried to intervene.

“This case adds to the growing pattern of vigilante attacks and killings of persons accused of sorcery in Papua New Guinea,” Cecile Pouilly, a spokeswoman for the Office of the High Commissioner for Human Rights, told reporters in Geneva.