In an interview to the Reuters news agency, Mr Modi said: "Even If I am in the back seat of a car and a puppy (kutte ka bachcha) comes under the wheels, isn't it painful? It is. Whether I am a chief minister or not, I am a human being - I will be sad if something bad happens anywhere." (Read the full interview here)
Samajwadi Party leader Kamal Farooqui slammed Mr Modi, saying, "It is a very sad, humiliating and disturbing statement. He is saying Muslims are worse than even puppies? He should immediately apologise to the people of this nation." (Read: Who said what)
"Speaking of anything that is hurtful, be it for a human being or an animal, there should be a sense of remorse. I don't think he felt the sadness that he spoke about," Union minister Salman Khurshid of the Congress told NDTV.
The BJP has said it is "despicable" to say Mr Modi compared a community to dogs. Party spokesperson Nirmala Sitharaman said, "People should read the interview. This is a complete misinterpretation leading to an unwanted controversy where one doesn't exist."
She explained that Mr Modi was in fact saying that "any human being would be saddened even if a puppy comes under a car. An expression used in relation to show that any human being would feel bad."
Mr Khurshid has suggested that Mr Modi should "speak less if he doesn't want to be misinterpreted."
The Janata Dal-United, which recently snapped ties with the BJP, said Mr Modi seemed to have lost his mental balance. "The statement shows that Mr Modi is incapable of taking every community along."