Sri Lanka, May 4 -- Indian Prime Minister Narendra Modi's party was on course to win two of four crucial state elections on Monday (May 4), expanding its influence and weakening its key rival half-way into his third term in office.

Modi's Bharatiya Janata Party (BJP) was set to return to power in the eastern state of Assam for the third straight term, and was sweeping West Bengal, counting trends on the Election Commission website showed.

Both states border Bangladesh and infiltration into India was a key poll issue.

The BJP has never ruled West Bengal, a state where it had only three local lawmakers until 2021.

Modi, his closest aide and Home Minister Amit Shah and several senior BJP leaders have campaigned extensively in West Bengal...