Illegal migration into India, particularly from across porous eastern borders, has emerged as a critical na-tional security threat, with evidence suggesting that some illegal migrants are exploited as terror operatives. As prominently reported on the front page of the Sunday edition of this newspaper, the immigrant populations, being highly vulnerable, are being increasingly targeted by extremist and terror groups for recruitment, radicalisation, and logistics. This situation in turn has been complicating internal stability. Considering this threat, the Union government has recently asked all state governments to gear up detection and deportation of such individuals, be they from Bangladesh or Myanmar. But, as such drives have been launched, many such illegal immigrants who have been roped in by various terror groups having links to Islamic fundamentalist organizations in Bangladesh, Pakistan and other countries have gone underground at the behest of the terror groups. As reported, while socio-economic issues have compelled some people to illegally migrate to India, many individuals were also specifically sent to India by international terror rackets to take part in terror activities in India. Now, with the Government of India cracking down on illegal migrants as a whole, the terror operatives have been instructed to remain underground and wait for further instructions. They have been asked to gather information only about civilian departments. They are told to scan bus stands, railway stations and crowded markets. The individuals currently under scrutiny by the agencies are affiliated with either the Harkat-ul-Jihadi Islami (HuJI) or the Jamaat-ul-Mujahideen Bangladesh (JMB). Both terrorist groups report to the ISI and have been tasked with handling operations in West Bengal, the northeastern states, and certain parts of South India. Another group, the Ansarullah Bangla Team (ABT), has also been actively recruiting in India to create a foothold in the region. Terrorist groups based in Bangladesh and Pakistan have historically utilized illegal Bangladeshi migrants to fuel radicalisation, logistical support, and militant activities in India. The 4,000-km porous border, linguistic similarities, and socioeconomic marginalisation of migrants in slum areas create fertile ground for exploitation by extremist organizations. As reported, extremist groups normally house these illegal immigrants, who are tasked with carrying out attacks, in Kerala or Tamil Nadu. There are many camps which house Bengali-speaking people. These migrants blend in easily and stay part of this group.