A video shared widely in India shows two Christian women being paraded naked and groped by a group of apparently Hindu men before being dragged into a field where they were allegedly raped.

The women, one in her twenties and the other in her fifties, are seen pleading with the mob not to harm them as ethnic violence flared in the northeastern state of Manipur which shares a border with Myanmar. When the younger woman’s brother and father tried to protect them, officials said, the mob bludgeoned them to death.

Indian Prime Minister, Narendra Modi, reacted to the violence saying “The guilty will not be spared,” “What has happened to the daughters of Manipur can never be forgiven.”

Modi urged the heads of state governments to ensure the safety of women and said the incident, which took place on May 4, was “shameful for any civilised nation”.

The attack has sharpened focus on a conflict in Manipur that threatens to erupt into civil war. At least 140 people have been killed in the past two months as mobs rampaged through villages, attacking locals and torching houses.

The unrest was caused by a demand from the mostly Hindu Meitei people for special status that would let them buy land in the hills populated by Christian Kukis and other tribal groups, as well as getting a share of government jobs.