"The way in which party leaders breached the sanctity of Rajghat by dancing there is condemnable. The party should tender an apology to the people," he told reporters here.
"Yeh nachiyon ki party kab se ho gayi" (When did the BJP become a party of dancers?" asked Singh.
"The BJP belonged to an ideology which killed Mahatma Gandhi," the senior Congress leader said.
"With its leaders Sushma Swaraj and Vijay Goel dancing there (at the Rajghat, the memorial of Mahatma Gandhi, during their protest against the police action on Baba Ramdev and his followers), they have shown they belonged to this ideology."
Swaraj had defended her act saying she was dancing to the tune of patriotic songs to boost the morale of party cadres which is in keeping with traditions of the BJP.
Taking potshots at BJP leader L K Advani, Singh said he should be ashamed of his statement comparing Jaliawalan Bagh with Ramlila Ground.
"He has insulted the martyrs of Jaliawalan Bagh," he said adding "BJP's comparision of Swami Vivekanand with that of Ramdev was unforunate and an insult to Vivekanandji".