Mr Singh, who was expelled from the Samajwadi Party, said, "An open death threat was issued against me by Akhilesh supporter", and alleged that senior SP leader Ram Gopal Yadav may "target" him.
"Main hoon Ram Gopal ke target pe, woh khule aam meri hatya ki chunauti de rahe hain ki main UP se surakshit wapas nahin jaunga (I am a target of Ram Gopal. I won't return from UP safe as he is openly issuing death threats to me)," he told reporters in Varanasi.
"I fear that I may be killed," he said.
Referring to 'Z-category' security cover accorded to him by the central government, he said, "Ram Gopal Yadav even knows the reason why I received the security."
He asserted he had always been "Mulayamwadi", but rued that now even Mulayam Singh Yadav has become "Akhileshwadi". Mr Singh said after his expulsion from the party, he was like a "khula saand" (a free bull) in search of greener pastures.
The MP said that he, Mulayam Singh Yadav and Shivpal Yadav have been sent on a 'vanvaas' (exile) by Akhilesh Yadav.
Mr Singh was in Varanasi to attend the condolence meeting of Garhwa Ghat Ashram head Guru Harigyananand who passed away a week ago.