India will identify and expel illegal immigrants from across the country, the interior minister said on Wednesday. Critics say the stepped-up campaign could stoke religious tension and further alienate minority Muslims.

An exercise to identify alien immigrants from Muslim-majority Bangladesh has been going on in the northeastern state of Assam for years. The campaign was a key issue in this year’s general election, won by PM Narendra Modi’s Hindu-nationalist party.

Home Minister Amit Shah told parliament that the government would not limit its efforts to Assam, but would come down hard on illegal immigrants anywhere.

Shah called illegal migrants “termites” that he said were eating into Assam’s resources during the election campaign, Reuters reports.