The Election Commission on Saturday sought explanations from the party presidents of the BJP and the Congress regarding the comments made by their main campaigners Amit Shah and Rahul Gandhi.
The comments allegedly violate the poll code.
BJP's J.P. Nadda and Congress's Mallikarjun Kharge have to submit their responses by 1 am on Monday, two days ahead of the voting in Maharashtra and Jharkhand.
In its counter-complaint, Congress alleged that Home Minister Amit Shah delivered a "slew of false, divisive, malicious, and slanderous statements about the Indian National Congress (INC) and its allies" during an election rally in Dhanbad on November 12.