Hundreds of troops have been deployed to quell deadly riots and clashes between Hindus and Muslims sparked by the killing of three villagers who had objected when a young woman was being harassed in northern India.

Police said 19 people were killed, including an Indian broadcast journalist, a police photographer and several people who on Sunday succumbed to injuries received a day earlier when the two groups set upon each other with guns and knives in Kawal village, in the state of Uttar Pradesh.

The violence quickly spread to neighboring villages in Muzaffarnagar district Saturday night.

"A curfew has been imposed in three riot-hit areas of Muzaffarnagar," said the head of the state's home ministry, R.M. Srivastava. "The situation is still very tense, but under control."

Soldiers were going door to door to search for weapons. A state of high alert was declared for the entire state of Uttar Pradesh, which has a population of 200 million people.

The clashes broke out Saturday after thousands of Hindu farmers held a meeting in Kawal to demand justice in the Aug. 27 killing of three men who had spoken out when a woman was being verbally harassed.

The state's minority welfare minister, Mohammad Azam Khan, said some at the meeting gave provocative speeches calling for Muslims to be killed.

The farmers were attacked as they were returning home after the meeting, senior police official Arun Kumar said.

"The attack seemed well planned," Kumar said. "Some were armed with rifles and sharp-edged weapons."

Gunfire was reported from several areas of the village. Within hours clashes broke out in neighboring villages, Kumar said.

A leader from the Hindu nationalist Bharatiya Janata Party said tensions had been simmering since the three men were killed Aug. 27 in a tea shop.

"Had the killers been arrested, the situation might not have gone out of hand," Vijay Bahadur Pathak said.

Uttar Pradesh was at the heart of some of India's worst communal clashes in December 1992, after a Hindu mob razed the 16th-century Babri mosque in Ayodhya.

The government has warned that India is seeing a rise in communal violence, with 451 incidents reported already this year, compared with 410 for all of 2012.

Tensions were expected to escalate in the run-up to next year's national elections, Home Minister Sushilkumar Shinde told reporters in New Delhi on Saturday. He said all 28 of India's states should stay alert and improve their ability to gather intelligence.

Communal violence last month left two dead and 22 injured in a village in Bihar state, east of Uttar Pradesh, according to Indian media. Outbreaks have also been reported recently in Uttar Pradesh's district of Shamli, as well as in the disputed Himalayan territory of Kashmir.