Security was tightened Friday in the Indian state of Assam for the release of a citizens' list that could potentially lead to several million people becoming stateless, most of them Muslims, in a process the government wants to replicate nationwide.
Those left off the National Register of Citizens (NRC), due to be published Saturday, face losing their citizenship, being put indefinitely into camps or deported - to the alarm of UN rights experts and activists.
Authorities in Assam in north-eastern India, for decades a hotbed of inter-religious and ethnic tensions, have brought in 17,000 additional security personnel with gatherings banned in soma areas and "cyber units" scanning social media.
Assam, an isolated state of 33 million, has long seen large influxes from elsewhere including during British colonial rule and around the 1971 war of independence in neighbouring Bangladesh.
Pressure for a lasting solution has been growing for decades from those who see themselves as genuine Assamese. Sporadic violence has included the massacre of around 2,000 people in 1983.
Critics of Prime Minister Narendra Modi's Hindu nationalist Bharatiya Janata Party (BJP), which also runs Assam, say the NRC process reflects its aim to serve only its co-religionists.
In January India's lower house passed legislation that stands to grant citizenship to people who moved to India from Bangladesh, Pakistan and Afghanistan as recently as six years ago -- but not if they are Muslim.
Home Minister Amit Shah, Modi's right-hand-man, has called for the ejection of "termites" and said before the BJP's thumping re-election victory in May that it would "run a countrywide campaign to send back the infiltrators".
- 120 days -
Only those who can demonstrate that they or their forebears were in India before 1971 can be included in the NRC.
But navigating the complex process is a huge challenge for many people in a poor region where illiteracy is rife and where many lack documentation.
The roughly two million people who are expected to be left off the final NRC register -- although estimates vary -- will have 120 days to appeal at special Foreigners Tribunals, which the government says are being expanded.
But critics say that tribunal members can be underqualified and are subject to "performance" targets, and that the entire process has been riddled with inconsistencies and errors.
"We are genuine Indian people. My forefathers were born here in this land," Saheb Ali, 55, one of around four million left off a draft NRC last year, told AFP.
“My mother's name was included in the voter list of 1966. We have submitted the documents while filing the forms. However, her name is not there in the draft NRC,” said Ali.
- Camps and suicides -
Those rejected by the tribunals and exhausting all other judicial possibilities -- the government has promised legal aid -- can then be declared foreigners and be put in one of six detention centres.
Ten new such camps have been announced. One with space for 3,000 is being constructed in Goalpara west of Assam's capital Guwuhati.
The camps currently hold 1,135 people, according to the state government, and have been operating for years.
Nur Mohammad, 65, for instance spent almost 10 years in one such camp until a Supreme Court order saw him released this month.
"I just want to ask them what is my crime? I was born here and lived in Assam all my life," he told AFP. "I don't know if my name will be in the NRC or not."
Media reports say that there have been more than 40 cases of suicide caused by the worry about the NRC.
Samujjal Bhattacharya from the All Assam Students' Union (AASU), a key driver behind the NRC, said the register was necessary to protect Assam's indigenous "sons of the soil".
"We are not ready to live here like a second-class citizens in our own motherland," he said. "India is for Indians, Assam and the northeast is in India, and so Assam and the northeast is for Indians and not for illegal Bangladeshis."