"The situation in most parts of the district is peaceful... a holiday has been declared for all educational institutions in the district," Collector N Arun Roy told PTI.

Prohibitory orders are still in force, he added.

With two more persons succumbing to injuries at a hospital late last night, the toll in the firing rose to seven.

In Chennai, Chief Minister Jayalalithaa told the state Assembly that a retired High Court Judge would probe the firing incident which, she indicated, could have been the culmination of communal tension.

"Some of you (opposition members) who spoke here said it was not communal violence. If it be so, we are also happy. But the fact is that derogatory remarks were written on a wall in Mandalamanickam pacheri village (Ramanathapuram district) against Pasumpon Muthuramalinga Thevar (a highly respected nationalist leader)," she said.

"Following this a Class XI student Palanikumar from the village was killed on September 9. Then (Dalit leader) John Pandian leaves (to pay homage on the death anniversary of Dalit leader Imanuel Sekaran) and violence breaks out. Therefore, all these incidents have happened in an inter-connected chain-like fashion," she said.

In the wake of the boy's killing, Ramanathapuram Collector had banned entry of Pandian into the district as the situation there was tense, Jayalalithaa said, adding, despite that Pandian proceeded towards Paramakudi, following which he was arrested at Tuticorin.

30 buses and 15 police vehicles had been damaged in the violence which broke out yesterday after news spread that Pandian had been arrested en route to Paramakudi to pay homage to Sekaran on his death anniversary.

Police burst tear gas shells and made a lathicharge on people particularly dalits before firing at the stone-pelting crowd. Several people and police officials, including DIG Sandeep Mittal, were injured in the stone pelting.

Police also fired to quell violence in Madurai in which two persons were injured.
57 persons were arrested in Tirumangalam and more than 50 in Paramakudi for indulging in violence, police said.

Jayalalithaa had defended the police action yesterday, saying they were forced to open fire as the protesters attacked police personnel on duty. She also blamed some people for instigating the violence "for their own political gains."

"The protesters indulged in large-scale violence and torched police vehicles. Police opened fire in self defence and to protect public property", Jayalalithaa, who announced Rs one lakh compensation to the next of kin of those killed, said.