New Delhi, May 13 (IANS) The Samajwadi Party (SP) Thursday said it will file a case of caste discrimination against Bharatiya Janata Party (BJP) president Nitin Gadkari over his remarks against its party chief Mulayam Singh Yadav at a rally.

"His remarks reflect caste discrimination. We will take legal opinion and file a case against him," SP spokesman Mohan Singh told IANS.

Asked about Gadkari's apology over his remarks at the rally in Chandigarh, the SP spokesman said he should also apologise to crores of Dalits and people from backward classes and minorities who had been hurt by his remarks.

The SP leader said the Rashtriya Swayamsevak Sangh (RSS) claims to be a custodian of Indian culture but Gadkari, who has the backing of the RSS, had shown his bias against the Yadav leaders.

He said it does not behove the president of a national party to use such language.

Gadkari had at the rally Wednesday night accused Mulayam Singh Yadav and Rashtriya Janata Dal's Lalu Prasad of betraying the opposition on the recent cut motions in parliament.

"Bade dakarte the sher jaise, aur kutte ke jaise ban kar Sonia-ji aur Congress ke ghar par talve chatne lage' (these leaders were roaring like lions but later bowed like dogs to lick the feet of Sonia and the Congress)," he said.