Taking to Twitter Kishor said: “The idea of nationwide NRC is equivalent to demonetisation of citizenship....invalid till you prove it otherwise.”
“The biggest sufferers would be the poor and the marginalised...we know from the experience!!#NotGivingUp,” he added.
Kishor has publicly taken a stand contrary to that of his party on the citizenship law, and offered his resignation to the party chief Nitish Kumar on Saturday, as per reports.
According to sources, Chief Minister Nitish Kumar has not yet accepted Kishor's resignation.
Prashant Kishor, who has aired his concerns over the Citizenship (Amendment) Act, also deleted the party designation from his bio on Twitter.
Emerging from the chief minister's residence after the meeting, Kishor stuck to his stand.
Asked what the chief minister now thought of the NRC, which he had criticised, Kishor said Kumar has made his stand clear in the past and being the national president of JD(U), it is for him to make any fresh statement on the issue.
Kishor, who joined JD(U) in Sep last year, sought to make light of the comments made on him by party general secretary and leader in Rajya Sabha RCP Singh, though without naming him.
"He is a very senior leader of the party. If he says anything about me, I do not mind it. Nitish Kumar has told me to not worry about anything that any party leader says about me," Kishor quipped.