"A decision in this regard has been taken at the meeting of Quami Ekta Dal," party leader and Mukhtar's brother Afzal Ansari said.
The decision has been taken "to strengthen secular forces and avoid division of votes", he added.
"We will discuss our future course of action later. Now Samajwadi Party, Bahujan Samaj Party and Aam Aadmi Party have to decide how to defeat Modi," he added.
Mukhtar is currently lodged in Agra jail in the BJP MLA Krishnanand Rai murder case.
Mukhter, who contested the last Lok Sabha polls on a BSP ticket against BJP's Murli Manohar Joshi, lost the election by a small margin. Later he quit BSP and formed the Quami Ekta Dal.
Image: MLA of Quami Ekta Dal Mukhtar Ansari