NEW DELHI - India deployed paramilitary forces and imposed a curfew in the western state of Gujarat on Wednesday after violence broke out at a protest led by a powerful clan to demand more government jobs and college places.
Prime Minister Narendra Modi called for calm in the state he ran for more than a decade before leading his nationalist Bharatiya Janata Party (BJP) to victory in last year's general election.
"I appeal to the people of Gujarat to maintain peace. Violence will never achieve anything," Modi said in a statement broadcast on television.
At least half a million members of the Patidar, or Patel, community rallied on Tuesday in the city of Ahmedabad to demand changes to policies that, they argue, unfairly favour groups at the lower end of India's social order.
Clashes broke out after the arrest of the movement's leader, 21-year-old activist Hardik Patel, prompting police to fire tear gas and to baton-charge protesters.
"The agitators clashed with the police and members of the lower castes. They have burnt down nine police stations and over three dozen buses," P.C. Thakur, Gujarat's top police officer, told Reuters.
"We had to impose a curfew to control the clashes. Offices, trading houses and educational institutions will not open today."
The Patels, a wealthy business community in India and overseas, have been a driving force in the economy, dominating the thriving diamond trade, oil processing and textiles.
But they say that caste-based reservations deprive them of opportunities. They insist the government should put an end to affirmative action policies that favour Muslims, low-caste Hindus and Other Backward Classes - a collective term covering socially and educationally deprived groups.
Caste-based reservations have always been a sensitive issue in India, used often as a tool for what is called vote-bank politics.
In a speech he gave in May, Modi said that India must overcome its caste-based divisions.
Modi comes from a lowly caste included in the Other Backward Classes, and has made much of his rise to power from humble origins as the son of a tea seller.
Caste politics are likely to play a role in a forthcoming election in the state of Bihar, whose chief minister belongs to the Patel community and has sympathised with the Gujarat protesters.
Modi's BJP is targeting gains in Bihar, home to one in 12 Indians, to boost its representation in the upper house of parliament where it lacks the majority it needs to pass economic reforms.