Indian police are using facial recognition technology to identify suspects in a crackdown on farmers who over-ran parts of New Delhi this week, while leaders of the months-long protest movement struggled to contain rifts within their ranks.

“No culprit will be spared,” said SN Shrivastava, New Delhi’s police commissioner.

Thousands of farmers on tractors rode into the capital on Tuesday as demonstrations against Prime Minister Narendra Modi’s contentious agricultural reforms boiled over, overwhelming authorities.

Many protesters broke away from agreed routes to march towards the centre of the city, including entering the iconic Red Fort, ending in clashes with police.

The aftermath prompted infighting between the various farm organisations that banded together for the protests, many of whose members have camped on New Delhi’s outskirts since November. Two groups called off their participation.

The chaos at the heart of the capital rattled authorities and protest leaders alike. It threatened to further embitter the stand-off between Mr Modi’s government and farmers demonstrating around the country.

The majority of India’s workforce still depends on agriculture, making farmers among the most influential groups in the country and a vital political base.

Mr Shrivastava said nearly 400 police officers were injured in the violence. One protester died.

Police have detained nearly 70 people and registered 25 criminal cases, according to Mr Shrivastava. Local media put the number of detentions at 200, and said several protest leaders had been named in complaints.

Delhi police’s use of facial recognition in particular has previously proved controversial. Authorities used the technology in 2019 amid protests against a citizenship law that critics said discriminated against India’s Muslim minority.

Police have taken up facial recognition technology as a law-enforcement tool despite the absence of a national law to define limits on its use, alarming privacy advocates.

Prakash Javadekar, India’s information minister, urged authorities to take action against instigators of Tuesday’s violence, saying their actions “can’t be condemned enough”.

Farm leaders, however, distanced themselves from the brawl, arguing that their movement had been hijacked by outsiders.

Samyukt Kisan Morcha, an umbrella group co-ordinating the protests, called Tuesday’s violence “a deep-rooted conspiracy to knock down the peaceful and strong farmers’ struggle”.

The three agricultural laws against which farmers are protesting seek to modernise the sector by allowing greater private participation. Currently, farmers in many states sell their produce to state-run market yards at guaranteed prices.

The reforms would open up the sector by allowing private trade outside these government markets and enable contract farming between producers and companies.

Many economists argue that such reforms are long overdue but the laws provoked outrage when they were passed in September.

Many farm groups said they were not consulted, and have called the measures an attempt to weaken the state protections on which they depend.

For weeks Mr Modi’s ruling Bharatiya Janata party sought to negotiate with farmers without success. But opposition parties have alleged the BJP has not taken the farmers’ concerns seriously and helped to stir the violence on Tuesday.

Randeep Surjewala, a spokesperson from the Congress party, called it “a concerted conspiracy, aided and abetted by the Modi government”.

Jaswinder Singh, a rice and wheat farmer who took part in Tuesday’s protests, said he was saddened by the violence. He pointed to a bus with smashed-out windows, a damaged police van and a tractor with slashed tyres at a protest site in central Delhi.

“A few people were doing that, but not all over,” he said. “I feel guilty. It’s our public property.”

Additional reporting by Jyotsna Singh