Amnesty International calls on Indian authorities to protect the young women from being raped after an order by village elders.
Thousands have signed a petition to stop two Indian sisters being gang-raped and paraded around a village naked with blackened faces as punishment for their brother's "crimes".
Amnesty International has called on Indian authorities to ensure the safety of the young women after they were sentenced by village elders.
The organisation says Meenakshi Kumari, 23, and her sister, 15, have been ordered by a Khap Panchayat - a village council - to be raped and humiliated.
More than 100,000 people have now signed the online petition to stop the punishment being meted out in Baghpat, Uttar Pradesh.
The unlected, all-male, council made the ruling after their brother apparently ran away with a married woman from the village’s dominant Jat caste.
Amnesty's Gopika Bashi, speaking from Chennai in India, told Sky News: "Their brother ran away with a supposedly higher caste person in their village.
"The Khap Panchayat has ordered they be raped and paraded naked."
Ms Bashi told Sky News the councils were usually comprised of dominant caste men, describing the system as an illegal "kangaroo court".
"On many of the times, they order sexually violent punishment as part of their decrees," Ms Bashi said.
The sisters and their relatives, who are from the lower Dalit caste, have since fled the village and are seeking refuge in New Delhi.
Amnesty said the older sister has filed a petition before India's Supreme Court seeking protection for her family so they can return home.
On 18 August, the Supreme Court ordered Uttar Pradesh authorities to reply to the petition by 15 September.
But one of their brothers told Amnesty: "After we went to the Supreme Court, the villagers are even more aggressive.
"In the panchayat, the Jat decision is final. They don't listen to us. The police don't listen to us. The police said anyone can be murdered now."
Amnesty said the family had also lodged a complaint with the National Human Rights Commission and the National Commission for Scheduled Castes.
They allege harassment by the police and the dominant caste family.
It said the family were also concerned for the safety of the Jat woman, who eloped with the brother.
The brother, 22, and and the woman, 21, had apparently been in love for three years, according to the The Hindustan Times.
But the woman's parents married her off to a young man from the Jat caste, against her wishes in February, the paper reported.
It is further reported that a month after her marriage, the woman fled the matrimonial home and eloped with the brother.
The couple surrendered after the alleged torture of family members, it is claimed.
The young man has been arrested under a drug charge and he remains in jail, the Hindustan Times added.