A crackdown on unlicensed slaughterhouses in India's most populous state has spread to others ruled by Prime Minister Narendra Modi's party, as Hindu hardliners press a political agenda that risks alienating the country's Muslim minority.

For years right-wing Hindu groups have demanded an end to the slaughter of cows, which are considered holy in Hinduism.

But most of the beef produced in India comes from buffalo rather than cattle, prompting some critics to suggest the latest move is motivated by politics and religion.

Rajiv Tuli - spokesman of the Rashtriya Swayamsevak Sangh, the ideological parent of the Hindu nationalist Bharatiya Janata Party (BJP) - said on Wednesday the party is only implementing "the rule of the land" in Uttar Pradesh state.

"If it is legal, nobody has a right to stop it. But if it is illegal, why should this be allowed to function?" Tuli said.

The closure of the abattoirs was launched after Modi appointed Yogi Adityanath as chief minister of Uttar Pradesh following BJP's landslide victory in state elections this month.

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Adityanath ordered the closure of slaughterhouses operating without licences soon after taking over on March 18.

Several other BJP-ruled states - including Jharkhand, Rajasthan, Uttarakhand, Chhattisgarh and Madhya Pradesh - have since followed suit, ordering the shutdown of meat-processing factories.

The crackdown mostly affects the country's Muslim community, which dominates the meat industry and makes up 14 percent of India's 1.3 billion people.

Abdul Faheem Qureshi, president of the Muslim All India Jamiatul Quresh Action Committee, which represents the cause of meat-sellers, said his organisation was considering legal action.

"Even we respect Hindu sentiments and are against cow slaughter," Qureshi said. "But this is being carried out only for political gains."

'Cow vigilantes'

The move by a number of state governments has also led to "a huge sense of apprehension in the minority section", said Neerja Chowdhury, a political commentator.

"The debate is beyond legal and illegal. Only recently cow vigilante groups have burned down slaughterhouses, creating an environment of insecurity," Chowdhury said, referring to a series of attacks in Uttar Pradesh.

India is one of the largest exporters of buffalo meat, selling $4bn worth in the 2015-2016 fiscal year. Its biggest buyers included Vietnam, Malaysia and Egypt.

Uttar Pradesh is the biggest producer of buffalo meat in the country, and exporters said the latest crackdown will hurt business.

"Right now everyone is very scared because they don't know whether what they are doing will be termed as legal or illegal," said Priya Sud, partner at Al Noor Exports, which operates slaughterhouses in Uttar Pradesh.

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Muslims working in the meat industry are fearful for their jobs and meat-sellers in Uttar Pradesh have gone on strike in protest.

"Supply of all kinds of meat has been disrupted due to the new rules," said Iqbal Qureshi, president of the Meat Murga Vyapar Kalyan Samiti, a meat-sellers' group.

Meanwhile, Hindu vigilantes forcibly shut down a KFC outlet in Haryana state on Tuesday for selling chicken during the nine-day Hindu festival of Navratra, when devotees fast and stay away from eating meat.