The Congress has accused Asaduddin Owaisi's AIMIM of undermining its votes base in Bihar's crucial Seemanchal region to help the BJP, which is set to emerge as the single-largest party in the state. Adhir Ranjan Chowdhury, a senior Congress leader, described Mr Owaisi as a "vote-cutter" and asked secular parties to be "alert" about him.
"BJP's tact of using (Asaduddin) Owaisi sahab's party in the Bihar elections has succeeded to an extent. All secular parties should be alert about vote-cutter Owaisi sahab," he was quoted as saying by news agency ANI.
Mr Owaisi's party had fielded 14 candidates in the region, which has a sizeable Muslim population. The JDU-led National Democratic Alliance (NDA) is leading in several of the region's seat.
AIMIM is also leading in some seats in the region, dashing the Congress's hopes of sweeping the election here.
At the time of writing this report, NDA was leading in 124 seats and the opposition alliance in 110, the Bihar counting trends showed. The BJP is leading in 75 seats, the JDU in 41. The RJD is ahead in 72 seats, the Congress in 20 and the CPI-ML in 11 seats.
The projections are not as per the opposition alliance's expectations, especially after the exit polls predicted an easy win.
However, the Tejashwi Yadav-led alliance is giving a tough fight to the ruling coalition. With several rounds of counting remaining, the electoral contest is expected to go down to the wire.