The Congress described this likelihood as a "very dangerous mistake" and said it was ready to fight the parliamentary polls alone in the state.
At a meeting in Kannauj, he also said, Our coming together has not only created fear in the BJP but also in the Congress."
Smaller parties like the RLD and the Nishad Party are also likely to be part of the alliance, but were not mentioned in the announcement on the press conference.
RLD's state unit president Masood Ahmed told PTI that the party national vice president Jayant Chaudhary will be in the state capital Saturday and, if invited, could be a part of the joint press conference.
"We may have fallen on difficult times. But I think to ignore us can prove to be a very dangerous mistake, he told reporters when asked about the possible SP-BSP alliance.
Since everybody realises that, I think we will have a happy and harmonious solution sometime in the near future," he added.
"We alone have 45 seats in the Lok Sabha and it is any day many more than the regional players, he said.
A 'mahagathbandhan' in the Lok Sabha elections needs to be built around the party having a national face," Bakshi said.
Sources said the SP and the BSP are planning to contest on 37 seats each out of the 80 on offer in Uttar Pradesh and plan to leave just two, Rae Bareli and Amethi, the bastions of Sonia Gandhi and Rahul Gandhi, for the Congress.
Congress leaders like PL Punia, who delivered Chhattisgarh to the Congress as its state in-charge, and UPCC chief Raj Babbar are reportedly of the view that the party should seek its pound of flesh in any alliance.
They cite the example of 2009 when the Congress romped home with 22 Lok Sabha seats in UP, surprising many.
Shah claimed that the BJP is on its way to win more than 50 per cent votes in Uttar Pradesh, asserting the saffron alliance's tally will improve from the 73 Lok Sabha seats it won in 2014 out of the state's 80.
Last year, Yadav and Mayawati decided to bury their differences to contest three bypolls.
The joint opposition victories in the bypolls in Gorakhpur, Phulpur and Kairana was seen as a consolidation of Other Backward Classes, Dalits and Muslim votes, and raised expectations of a similar math working in the 2019 elections.
In recent days, Yadav and Mayawati have put out press statements that mention a "gathbandhan".
"Don't be shaken," she advised him.
Yadav returned the favour when he put out a statement to condemn Modi's remarks in Agra on Mayawati "forgetting" an attack on her by SP workers in 1995.
"The PM is scared of the alliance," Yadav said.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)