Congress today stuck to its demand for an apology from Prime Minister Narendra Modi for his remarks against his predecessor Manmohan Singh in the Rajya Sabha, describing his jibe as "unheard of in Indian parliamentary democracy". "We are very very disappointed by what the PM said yesterday. I do not think in the history of Indian parliamentary democracy, we have ever heard the PM insulting his predecessor in such a manner using bathroom analogy. This is simply not heard of (before)," Congress MP Sashi Tharoor said outside Parliament. Seeking withdrawal of the statement, he said, "In politics, there can be differences but you will never find this kind of statement in our parliamentary debate. PM should withdraw such remarks. There are political differences in our country. In election campaign, people say rude things to each other. But in the House, certain decorum must be maintained. We feel strongly that it should not have happened." You May Also Want To Watch: "We have asked for an apology because he has not withdrawn it so far. If he withdraws it, then the matter will end. But if he does not withdraw, then apology is the only way in which he can make up for the hurt he has caused unnecessarily," the former Union minister said. Replying to a debate on the Motion of Thanks to the President's Address in the Rajya Sabha yesterday, Modi had attacked Congress and taken on Singh who had described demonetisation as "organised loot" and "legalised plunder", saying "the art of bathing in a bathroom with a raincoat on" is known only to the former Prime Minister as there is "no blot on him" despite "all the scams". This provoked an angry reaction from Congress members who staged a walkout in the midst of the reply by the Prime Minister.