NEW DELHI: Three Indian opposition state assembly members and more than 50 municipal leaders from West Bengal joined Prime Minister Narendra Modi's party on Tuesday, days after he was re-elected with big gains in places like the populous eastern state.

The defections came as opposition parties in states such as Karnataka, Madhya Pradesh and Rajasthan scrambled to stop their regional legislators from switching to Modi's powerful Hindu nationalist Bharatiya Janata Party (BJP).

With a near two-thirds majority secured in the 545-member lower house of parliament, the BJP is now targeting state assemblies to consolidate its power.

It is the state assemblies that elect members of the upper house of parliament, where Modi's ruling coalition does not have the majority necessary to pass contentious legislation.

"We don't want to topple the state government, but their own people want come to us," Kailash Vijayvargiya, a BJP national general secretary, said after the new members of the party were introduced to the media in New Delhi.

"They don't want to stay with their party. We won't stop them."

West Bengal sends the third-largest number of members to the lower house of parliament and was a battleground state in the recently concluded general election.

The BJP won 18 of 42 seats there, compared with just two five years ago.

Almost all the people joining the BJP on Tuesday were from the Trinamool Congress, led by the state's chief minister, Mamata Banerjee, who is one of Modi's biggest critics.

Modi said during campaigning last month that at least 40 Trinamool state lawmakers were in touch with him and would leave the party soon.

Trinamool has an absolute majority in the West Bengal assembly and there is no threat to the government there.

But Vijayvargiya told Reuters about 10 more West Bengal state lawmakers could join the BJP before a state assembly election there in 2021.

A Trinamool official said the people of West Bengal were still with Banerjee.

The BJP and Trinamool are bitter rivals and clashes between their supporters forced the Election Commission to halt campaigning in the state a day early.