BHUBANESWAR, May 19: Resentment is brewing in the rank and file of the Biju Janata Dal (BJD) over the leadership's obvious lack of concern towards the by-polls. Though the party's main rival Congress has launched its election campaign in the five constituencies which are going to the polls on June 3, the BJD top brass is still busy trying to sort out the differences in its leadership. The ongoing bickering between the BJD and its ally Bharatiya Janata Party has also come as a dampener for the regional outfit.The BJD, which is contesting from three out of the five constituencies, is yet to formulate its election strategy for the ensuing polls. Though party president and Union minister Naveen Patnaik has been here for the last few days, he is yet to start campaigning. Sources in the BJD alleged that lack of coordination between the top leaders is hampering the party's campaign.But the Congress, on the contrary, has publicly ended all internecine battles in view of the by-polls. Chief Minister J B Patnaikand president of the Orissa Pradesh Congress Committee (OPCC) Hemananda Biswal jointly launched the party's campaign at Bhandaripokhari.On the other hand, top leaders of the BJD, including party president Naveen Patnaik and chairman of its Political Affairs Committee (PAC) Bijay Mahapatra are yet to act jointly. This has proved that the differences between Patnaik and Mahapatra have not been sorted out. Mahapatra was present at Bhandaripokhari when the party's candidate Rath Das filed his papers. Besides, Mahapatra along with other leaders addressed the first workers meet of the BJD at Bhandaripokhari. However, Patnaik chose to absent himself from the workers' meet.