Security has been tightened in a northern Indian town after eight people, including four protesting farmers, died on Sunday.
Violence broke out in Lakhimpur Kheri district of Uttar Pradesh state during a protest against agricultural reforms.
Photos and videos on social media showed vehicles set on fire as people lay covered in blood.
Opposition leaders have been stopped from visiting the families of the victims as the situation remains tense.
Farmers alleged that clashes erupted after a car from a federal minister’s motorcade ran over two protesting farmers – a charge the minister denies.
Several prominent farm leaders, including Rakesh Tikait, reached the violence-hit district on Monday morning. Mr Tikait told the media that farmers will hold discussions with the villagers before deciding their future course of action.
Akhilesh Yadav, former Uttar Pradesh chief minister, told the BBC that the police had stopped him from leaving his residence.
“The prime minister says ours is a vibrant democracy. But stopping opposition leaders from going to Lakhimpur doesn’t really strengthen our democracy. Farmers, who are the backbone of our economy, cannot be treated like this,” he said.
“Their fears are legitimate about private players hurting their income and they should be heard. We need to strengthen our farming systems and not weaken them.”
Senior Congress party leader Priyanka Gandhi was also detained on Monday while she was on her way to meet the families of farmers who died in the violence.
Violence in Lakhimpur Kheri marks a dramatic escalation in a 10-month-old protest against agriculture reforms that farmers say will benefit private players at their expense.
Tens of thousands of them have been striking on the outskirts of Delhi since November, demanding that the laws must be repealed.
It is one of the longest farmers-led protests India has ever seen, pitting the community against Indian Prime Minister Narendra Modi and his Bharatiya Janata Party-led (BJP) government.
How did the violence start?
Farm leaders alleged that Sunday’s violence started after federal minister Ajay Mishra’s son drove his car into a group of protesters.
Farmers had assembled in the district to protest against the visit of Mr Mishra and deputy chief minister Keshav Prasad Maurya.
The protesters were angry with Mr Mishra over his earlier statement in which he said the protests involved just “10-15 people” and that “it would take just two minutes to make them fall in line”.
They had been staging a demonstration on the road when the minister’s motorcade allegedly ran over them, killing two protesters and injuring others, farming unions say.
But Mr Mishra has denied the allegations and said his son was not in the car at the time of the incident.
He alleged that farmers threw stones at his vehicle, which led to the driver losing control and ramming into the protesters.
In subsequent violence, three members of the ruling Bharatiya Janata Party (BJP) and the driver was beaten to death, he added.
“If my son would’ve been there, he wouldn’t have come out alive,” Mr Mishra told news agency ANI.
Police have confirmed the toll, but have not made any arrests so far. They said the four people who were in the car were among those who died in the violence.
Why are the farmers protesting?
Thousands have been rallying against the changes for months, blocking major streets in the capital Delhi.
Taken together, the laws will loosen rules around sale, pricing and storage of farm produce – rules that have protected India’s farmers from the free market for decades.
They also allow private buyers to hoard essential commodities for future sales, which only government-authorised agents could do earlier; and they outline rules for contract farming, where farmers tailor their production to suit a specific buyer’s demand.
Farmers fear the laws will eventually lead to the end of wholesale markets and assured prices, leaving them at the mercy of big corporations.
Many of them have refused to return to their farms until the laws are repealed – and they have stayed through a harsh winter, a deadly second Covid wave and a scorching summer.