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.
The BJP had filed a complaint against Rahul Gandhi, claiming that the Congress leader, "falsely accused other states of stealing and snatching alleged opportunities from the State of Maharashtra" in a speech in Mumbai on November 6.
"Rahul Gandhi with his misleading statement has tried to create a divide between the people of Maharashtra and Gujarat & other states," said the BJP in its complaint on November 11.
"His statements are inciting the youths of Maharashtra which is immensely dangerous for the unity and integrity of the nation," it added.
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.
"During his speech, Amit Shah alleged that the INC and its allies were; (a) against Scheduled Caste (SC), Scheduled Tribes (ST), and Other Backward Classes (OBCs); (b) promoting terrorism in the country," Congress said in its complaint on November 13.
"In what has become a common narrative across the BJP's campaign in Jharkhand, Amit Shah has also accused the INC of planning to take away reservations from members of the ST, SC and OBC communities and granting them to members of a particular religious minority community," it added.