Lucknow, June 21 - The Samajwadi Party (SP) Thursday lashed out at Congress spokesman Rashid Alvi for making snide remarks on party chief Mulayam Singh Yadav.

Regretting that the comments came from a Congress leader, SP spokesman Rajendra Chowdhary called for an unconditional apology by Alvi or an explanation by the Congress.

Alvi told an election rally in Moradabad Wednesday that Mualayam Singh Yadav was the "biggest agent of the BJP" (Bharatiya Janata Party).

"I have been saying this for the last 10 years and I will always say so," Alvi said.

SP general secretary Ram Gopal Yadav also came down heavily on Alvi and, without taking his name, said "mad people" who said baseless things should be sent to a mental asylum.