The Indian army was called in to contain communal violence pitting Hindus against Muslims that killed at least 21 people in northern Uttar Pradesh state.

Fresh rounds of violence erupted in far-flung rural pockets of the state yesterday.

The state administration clamped shoot-at-sight orders in a desperate attempt to quell the tempers running high on both sides following a "mahapanchayat" organised by the Bharatiya Kisan Union (BKU) on Saturday.

A curfew was imposed in three districts.

Briefing the media, Muzaffarnagar District Magistrate Kaushal Raj Sharma confirmed 21 deaths in the clashes so far. However, locals claimed that many more were killed in the rural areas. Illegal firearms, iron rods, swords, knives, sticks, bricks and stones were used in clashes.

"We have arrested 52 people and seized weapons. Efforts are on to identify the others involved," said Sharma.

An army contingent of up to 800 was

dispatched to the area on Saturday night, as armed gangs of Jats, a group practising Hinduism, stormed a mosque and a village with Muslim residents, the state’s principal home secretary RM Srivastava said.

The violence erupted on Saturday following a meeting attended by Jats in Muzaffarnagar district, 140 km northeast of New Delhi. Police said 10 people died, including a journalist and photographer, and about 3 5 were injured.

The Jats are demanding the rescinding of charges against members of their community in connection with a communal clash last month in which three people were killed.

Arun Kumar, a senior police official, said tensions were fuelled by an online video purporting to show the killing of two Muslim youths last month.

Local media said about 50 outbreaks of communal tension have occurred in populous Uttar Pradesh since the region's Samajwadi Party came to power last year. More than 25 people have died.