With two more persons succumbing to injuries at a hospital, the death toll in the police firing on a stone-pelting mob of Dalits, who indulged in violence following detention of their leader John Pandian, has risen to seven, police said on Monday.

Two persons identified as Teerpukani and Vellaichamy succumbed to injuries late Sunday night.

Officials have suspended bus services to the rural areas in the sensitive districts, including Ramanathapuram, Madurai, Sivaganga and Virudhunagar as a precautionary step.

Additional police reinforcement have been brought from Tiruchirappalli, police said.

Violence broke out on Sunday after news spread that Pandian had been detained at Tuticorin en route to Paramakudi when he was on his way to pay homage to dalit leader Imanuel Sekar on his death anniversary.

Police used tear gas and batons before firing at the crowd at Paramakudi. Several people and police officials, including DIG Sandeep Mittal and SP Senthil Velan and DSP Ganesan were injured in the stone pelting. More than 15 vehicles were set ablaze in the violence.

Police said they had arrested 57 persons in Tirumangalam and more than 50 in Paramakudi for indulging in violence.

Local dalit leaders blamed police for not making proper arrangements to manage the huge crowd expected for paying homage to the dalit leader.

However, defending the police firing, chief minister Jayalalithaa had on Sunday blamed some people for disrupting law and order "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.