The Congress had earlier denied the allegation by Jyotriaditya Scindia on Saturday.
Former Madhya Pradesh Chief Minister Kamal Nath on Sunday rubbished BJP leader Jyotiraditya Scindia's allegation that he was called a "dog" by the Congress leader.
"Yesterday Jyotiraditya Scindia said that I had called him a dog in Ashoknagar. I had neither addressed him as a dog nor will I do so, people of Ashoknagar are witness to this," Kamal Nath was quoted as saying by news agency ANI at a news conference in Gwalior.
Competing for the shrillest elections in recent memory, the Madhya Pradesh by-polls inducted a new contender on Saturday with BJP MP Jyotiraditya Scindia claiming that Kamal Nath, already censured for calling a female politician an "item", has now called him a "dog".
"Kamal Nath ji came here to Ashoknagar and called me a dog. Haan, Kamal Nath ji, main kutta hoon (Yes, I am a dog) because the public is my master. Yes, I am a dog, because a dog protects its master," Mr Scindia addressed his former Congress colleague at a campaign rally.
The Congress quickly denied the allegation, with a spokesperson for Mr Nath telling news agency PTI that the former chief minister never used such a word for Mr Scindia or any other leader. "Kamal Nath never used this word for anybody in his speeches," Narendra Saluja said.
However, shortly after Mr Scindia's clip went viral, another video emerged of Congress's Acharya Pramod Krishnam speaking earlier at a rally in the same area, saying, "When Kamal Nath ji was trying to act against a mafia don here, someone protected him like a faithful dog." He did not name Mr Scindia.
Earlier in day, Kamal Nath took the Election Commission to court after it revoked his privileges as a "star campaigner" for a series of controversial remarks by the Congress leader including calling a BJP's Imarti Devi an "item".
Later, he had also said at a rally that Chief Minister Shivraj Singh Chouhan is a "nautanki kalakar who should act in films in Mumbai". He said: "Aapke Bhagwan toh woh maafia hai jisse aapne Madhya Pradesh ki pehchaan banai. Aapke bhagwan toh milawat-khor hain (Your god is mafia - an apparent attack on the chief minister)."
By-elections are being held on November 3 to fill 28 vacant seats in the Madhya Pradesh assembly. Most of these fell vacant when Congress leader Jyotiraditya Scindia revolted earlier this year and defected to the BJP, taking along 22 MLAs.
Kamal Nath's Congress-led government fell and the BJP returned to power. The BJP needs to win at least eight of these seats to stay in power. If at all the Congress manages to win all 28, it can make a comeback attempt.