India will conduct a national citizen survey to weed out those living illegally in the country, the government said on Wednesday.

Home Minister Amit Shah said people from all religions who can prove they are Indian citizens will be included in a National Register of Citizens (NRC). He did not give a time frame for the survey in the country with 1.3 billion people.

Shah's announcement in Parliament came months after a mammoth survey in northeastern Assam state, where about 1.9 million of the state's more than 32 million people were excluded from a registry as undocumented immigrants.

The state said those left out would have an opportunity to prove their citizenship at tribunals set up by the government. Shah today said the NRC exercise will be repeated in Assam when it is carried out in the rest of the country, according to The Hindu.

"People from all religions who are Indian citizens will be included. There is no question of any discrimination on the basis of religion," Shah said in response to concern that his Hindu nationalist-led government might target minority Muslims.

Major waves of refugees arrived in India after Partition in 1947, and in 1971, when Bangladesh broke away from Pakistan.

Critics accuse Indian Prime Minister Narendra Modi's Bharatiya Janata Party (BJP) of a deep-seated bias against minority Muslims and say the campaign against illegal migrants is aimed at Muslims, and threatens to further marginalise the community. The BJP denies the accusation and says it is opposed to the appeasement of any group.