West Bengal Chief Minister Mamata Banerjee's nephew and Trinamool Congress (TMC) leader Abhishek Banerjee was on Sunday assaulted by a man at a rally in East Midnapore district.
TMC spokesperson Derek O'Brien condemned the incident and said that his party would look into the entire episode.
"We will look into this and find out if any outsider was involved," he said.
The Bharatiya Janata Party (BJP) also condemned the incident, saying there is no place for violence in the politics
"The BJP condemns it. There is no place for violence in politics," said BJP general secretary Siddharth Nath Singh.
However, some political parties hinted at the assailant being a disgruntled TMC worker.
"This matter does not involve any outsider, it is an internal dispute of party," said Communist Party of India (CPI) leader Atul Anjan.