An earlier report, quoting Muzaffarnagar district administration officials, said the toll was 14.
On Saturday, at least six people, including a television journalist and a local photographer, were killed when two communities clashed after a "mahapanchayat" in Muzaffarnagar.
Mob of people pelted stones and exchanged fire. Around 40 people injured in the clashes were admitted to hospitals.
Violence started when some people pelted stones at a bus carrying people to the "mahapanchayat", where elders of two religious groups were meeting to sort out the simmering tension between the two communities ever since three youngsters were killed Aug 27 over a case of harassment.
Eight columns of the army, requisitioned from Bareilly, were sent to the violence-hit areas Saturday night after the violence spread to rural areas.
The situation was tense but under control, Additional Director General of Police (Law and Order) Arun Kumar told IANS Sunday.
Officials said four senior police officials were sent by the state government as "officers on special duty" to Muzaffarnagar and neighbouring districts, including Shamli, where tension has been reported.
Following the violence, curfew was imposed in the area Saturday night, and police have urged people not to step out of their houses in violation of the restrictions, and have warned trouble-makers not to further vitiate the atmosphere.
Director General of Police Devraj Nagar is monitoring the situation from Lucknow, and Chief Minister Akhilesh Yadav is learnt to have given a dressing down to senior officials.
"When tension was simmering for the last 10 days, the chief minister is angry as to why the violence, despite anticipation, was not contained in time," a close aide of Akhilesh Yadav told IANS Sunday.
With the monsoon session of the state assembly just a week away, Akhilesh Yadav is keen to end the hostilities at the earliest, the aide said.
Opposition parties, including the Bharatiya Janata Party (BJP), Congress and the Rashtriya Lok Dal (RLD), criticised the government, saying it has failed in maintaining communal harmony, peace, law and order in the state.
RLD state president Munna Singh Chauhan said the government has forfeited the right to continue in office.
BJP state spokesman Vijay Bahadur Pathak told IANS that the fact that the army had to be called in to contain violence in Muzaffarnagar has proved beyond doubt the "failure of the Samajwadi Party government in the state".
State Congress president Nirmal Khatri condoled the loss of life and said the government had failed to protect the interests and safety of the people in the state.
Akhilesh Yadav, meanwhile, said police have been pressed into service, and urged people not to be swayed by rumours.
"I urge people of the state to maintain peace, communal harmony and warn mischief makers," he told reporters on the sidelines of a meeting in the state capital.
--IANS (Posted on 08-09-2013)