Miscreants on Monday threw ink on farmer leader Rakesh Tikait during an event organised by a farmers' organisation at the Gandhi Bhavan in Bengaluru following which three people were arrested.
Soon after the incident, clashes took place between the organisers and the miscreants, with both sides attacking each other with plastic chairs.
The miscreants then allegedly shouted 'Modi-Modi'.
The High Grounds police have arrested three people in this connection.
Karnataka Home Minister Araga Jnanendra said, "We are in touch with the officers. Three people have been arrested and are being interrogated. I denounce this act. Everyone has got the right to freedom of expression under the Constitution."
He also dismissed the allegation that those who targeted Tikait were Bharatiya Janata Party leaders.
According to the organisers, the programme, which also included a press conference, was convened to "clear doubts" on farmer leader Kodihalli Chandrashekar following a sting operation against him, and Tikait was invited for it.
In the meeting, the miscreants appeared in the crowd posing as journalists and pretended to take notes.
One of them them then went to the stage apparently to adjust the microphone in front of Tikait and then tried to attack him with the mike.
Another person came there and threw ink on Tikait that stained his turban, face, white kurta, and green shawl worn around his neck.
Reacting to the incident, Tikait said the attack on him was in connivance with the state government.
"The local police is responsible for it and it happened due to the connivance of the government," Tikait told reporters.
He demanded an independent and fair investigation into the case to ascertain the credentials of the men who staged the attack. After the incident, Karnataka Congress chief D K Shivakumar called on the farmer leader.
The Aam Aadmi Party too condemned the assault.