The ruling BJP, often blamed by the opposition for a spike of mob killings in the country, hit back at the Congress, calling the 1984 anti-Sikh riots after former prime minister Indira Gandhi's assassination the country's "single biggest incident of mob lynching".
Home Minister Rajnath Singh, who was speaking on the opposition-backed no-trust motion against the NDA government, said mob killings should be stopped.
"But I want to say that the single biggest incident of mob lynching took place in 1984," he said.
Nearly 3,325 people were killed in the riots that broke out after Indira Gandhi's assassination by her body guards. In Delhi alone, according to the home ministry, 2,733 people died.
The home minister pledged to deliver justice to the families of people massacred over 30 years ago. A special team has been formed which is looking into these cases to bring the guilty to justice, he said.
Rajnath Singh's sharp statement is seen as a comeback to Congress president Rahul Gandhi who had earlier accused the BJP of spreading seeds of hatred among people that had contributed to many instances of mob killings.
India has been grappling with rising lynch-mob incidents since 2015 when a 50-year-old man Akhlaq was killed near Delhi because he was suspected to be in possession of beef.
In recent months, rumours spread over messaging service WhatsApp that a child kidnapping gangs on the prowl for victims have led to several deaths. A software engineer and his friends out on a drive were attacked by a mob last week in Karnataka's Bidar after rumours that they were part of a child kidnapping gang.
Ahead of the debate, Naresh Gujral, a senior leader of the BJP ally Akali Dal, had hoped that Prime Minister Narendra Modi speaks against mob killings in his reply to the debate on the no-trust motion "so that the minorities in this country feel reassured."
"My party is a party that represents a minority in this country. And we are concerned that there should be no insecurity in the minds of any minority," Mr Gujral, a Rajya Sabha member, told NDTV.