Six Telugu Desam Party activists were killed when police opened fire to quell a mob in Penukonda town in Anantapur district on Friday.
Trouble broke out when TDP candidate Paritala Sunita, widow of TDP legislator Paritala Ravi, went to the Revenue Divisional Office to file her nomination for the assembly byelection in Penukonda slated for June 2.
Thousands of TDP activists had participated in a procession to the office. When the party workers entered the office complex, the police tried to prevent them.
Fifteen policemen were injured and some police vehicles were damaged in the rioting. The police resorted to a lathicharge and fired in the air.
When the situation got out of control, the police fired on the mob, killing four party activists on the spot. Two others died later.
The TDP workers went on a rampage, attacking vehicles and public property.
Fifteen vehicles were damaged by the mob.
Police reinforcements from Anatapur town were sent to Penukonda to bring the situation under control.
The police clamped prohibitory orders under Section 144 of the Criminal Procedure Code. The police said the situation was tense with sporadic incidents of violence.
Andhra Pradesh Chief Minister Dr Y S Rajasekhar Reddy has ordered a magisterial inquiry into the violence and police firing.
He directed Home Minister K Jana Reddy and Director General of Police Swaranjit Sen to visit the town and monitor the situation.
TDP president and former chief minister N Chandrababu Naidu condemned the police firing. He appealed to party workers, supporters and leaders to maintain calm.
Andhra Pradesh Congress Committee President K Keshav Rao condemned the violence but blamed the TDP.
"By fielding Paritala Ravi in the assembly byelection, the TDP has spurned the Congress suggestion to keep factionists away from electoral politics. The TDP wants to win the byelection by hook or by crook. The violence indicates its sinister gameplan," he said.