Indian Home Minister Amit Shah has pledged to expel illegal migrants from the state of West Bengal, like in the state of Assam — by using the National Register of Citizens (NRC).

"The chief minister [of West Bengal] says she will not let NRC happen in West Bengal, but I am assuring you, each and every infiltrator in India will be shown the door," Shah said at a rally in the state capital, Kolkata (formerly Calcutta).

The state is now under the administration of the Trinamool Congress (TMC), a regional party led by Mamata Banerjee, who has been an opposition of Prime Minister Narendra Modi and his party.

NRC refers to a list of people who can prove they entered the West Bengal before March 24, 1971, one day before Bangladesh announced its independence from Pakistan.

The list has been recently implemented in northeastern Assam, and has stripped 1.9 million people of their citizenship, with a 120-day appeal deadline.

India's ruling Bharatiya Janata Party (BJP) distanced itself from the final list in Assam, but party workers in other parts of the country have been asking for it to be implemented in other states.