Indian Prime Minister Narendra Modi’s ruling Hindu nationalist party seized control of the opposition stronghold state of West Bengal in a key election Monday.

The Election Commission of India released partial results showing the Bharatiya Janata Party (BJP) won at least 124 seats in the 294-member West Bengal assembly, and was leading in 83 others. Final results are expected Monday evening.

It would be a significant breakthrough for Modi’s party, which had tried for years to dislodge the All India Trinamool Congress government led by Chief Minister Mamata Banerjee.

The BJP has never governed West Bengal, a politically influential state, where Banerjee – one of Modi’s most prominent critics – has held power since 2011.

Opposition parties have sharply criticized the polls in West Bengal after the Election Commission removed millions of voters from the electoral rolls.