Raju Kumar Sahu had said Congress and Left had funded protests over Rohith Vemula's suicide.
The Hyderabad University students' group, which has been leading demonstrations against the suicide of Dalit scholar Rohith Vemula, has said that
a former leader of the movement who resigned claiming corruption in the group had been "threatened" or "lured" away.
Raj Kumar Sahu, a leader of the Left-affiliated student's union SFI at the Hyderabad Central University, had resigned this week alleging that the agitation over the death of Mr Vemula is funded by the Congress and communist parties and has "become opportunistic."
Rubbishing the charges, the Joint Action Committee for Social Justice and members of SFI said they were "stunned and upset" with Mr Sahu's resignation and the allegations.
"It is highly disappointing and shocking that Raju Kumar Sahu who was an integral part of the struggle, backstabbed us over one night. We wonder what went wrong that he had to take that decision and his words started echoing of (rival student body) ABVP and (University Vice Chancellor) Appa Rao Podile," Arpita Jaya, a member of the JAC said.
Sanjay, a member of the SFI, said "It is quite unfortunate that Raju Kumar Sahu fell prey to ABVP and especially BJP politics. He must have got threats. He must have been lured into this, clearly."
The student parties denied the allegations of receiving political backing saying they had welcomed an intervention by the Opposition against the Centre.
"If our fight has to be sustaining, we need the support of these political parties. This is not for funds," Sanjay said.
Mr Sahu meanwhile has sought police protection, claiming he fears a threat from his former friends in the Ambedkar Students Association and the SFI.
Union Minister Venkaiah Naidu had tweeted after Mr Sahu went public with his charges, slamming the movement.Rohith Vemula, 26, was found hanging in his hostel room at the university in early January this year. In a suicide note he said he did not blame anyone for his decision to kill himself. But a month before that, he had sent a despairing letter to the University's Vice Chancellor Appa Rao about caste discrimination and said Dalit students should be given "a rope to hang themselves".
Students at the university have been on protest since Rohith's death, demanding the dismissal of Mr Rao and action against Union Ministers Smriti Irani and Bandarau Dattatreya, who they accuse of hounding Mr Vemula and his friends based on a complaint filed by leaders of the ABVP, the BJP's student wing, who study at the same university.
The central government has denied that Mr Vemula and others were persecuted.