NEW DELHI: Women in India's northeastern state of Manipur attacked the house of the main suspect in a sexual assault case that has enraged the nation, police said on Friday.

The person allegedly dragged two tribal women onto the streets in May and later incited a mob to rape and parade them naked, police said on Friday, as ethnic clashes engulfed the state.

The sexual assault took place over two months ago but it captured national attention after a short video went viral on social media earlier this week.

The main suspect, a resident of violence-hit Manipur state, was arrested on Thursday hours after Prime Minister Narendra Modi condemned the alleged sexual assault as "shameful" and promised tough action.

Three others also were arrested and a police official said were tracing at least 30 others involved in the crime.

"Local women pelted stones and burnt some parts of the house belonging to the prime accused in a village," said Hemant Pandey, a senior police official in capital city Imphal.

"We request women to protest peacefully as there is intense unease. We understand their rage," he said.

Protests were planned in several parts of India by rights groups demanding justice and swift investigations into the latest incident to raise questions about the safety of women in the country.

The sexual assault was reported by the victims in May after ethnic clashes began in Manipur. The fighting was triggered by a court order that the government should consider extending special benefits enjoyed by the tribal Kuki people to the majority Meitei population as well.

At least 125 people have been killed and more than 40,000 have fled their homes since the violence erupted.

"We want to know why police failed to take swift action when they knew that women were raped and paraded naked in Manipur," said Radhika Burman, a student in eastern city of Kolkata who is set to lead a public demonstration on Thursday.

Modi, who had not made any public remarks about the trouble in a state ruled by his Hindu nationalist Bharatiya Janata Party (BJP), spoke a day after the videos showing women being molested went viral.

Opposition MPs who have submitted notices in both houses of the parliament to discuss the violence in Manipur stalled the proceedings on Friday.

"Manipur needs complete attention and we demand the prime minister make an elaborate statement in the parliament," said Mallikarjun Kharge, the president of opposition Congress party.