A 44-year-old Congress worker died after he was attacked by an 18-member gang in Kerala's Chavakkad, police said on Wednesday.
The man, identified as Naushad, was a local Congress leader who was very popular in the area.
Naushad, who suffered serious injuries on the neck and hands, died on Wednesday morning at a hospital.
Three others were also injured in the attack.
Eyewitnesses said the armed attackers with their face covered came in motorcycles and attacked the four men at around 6.30 pm on Tuesday.
Leader of Opposition Ramesh Chennithala said the death was "painful" and the accused should be brought to charges immediately.
Terming it as a "political murder," KPCC President Mullapally Ramachandran said the police should ensure the accused, however high and mighty they may be, should be brought to book.
Naushad had worked as youth congress secretary in the area and was active as a local leader and his death was a big loss for the party, he told reporters in Thiruvananthapuram.
Condemning the incident, AICC secretary Oommen Chandy said the attack was "without any provocation".
"A group of people came with the intention to kill Naushad and Social Democratic Party of India workers were behind the attack," Mr Chandy alleged before reporters in Delhi.
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