Hundreds of people in India’s border region with Bangladesh have fled to the frontier, police said Wednesday, after the government ordered the construction of detention centres for undocumented Bangladeshi migrants and Rohingya refugees.

Indian Prime Minister Narendra Modi’s Hindu-nationalist Bharatiya Janata Party (BJP) swept to power in West Bengal state in early May with a hardline policy to “detect, delete and deport” illegal migrants.

India’s right-wing have long argued that illegal migration is a national security threat, and warned of changing demography in India’s border states.

West Bengal government’s last week ordered the setting up of “holding centres” for “apprehended foreigners”, singling out both Bangladeshis and Rohingya.

The decision has fuelled anxiety among West Bengal’s roughly 35 million Muslims, many of whom share linguistic and cultural ties with neighbouring Bangladesh.

Indian police officer Shirshendu Pati, from the Swarupnagar Police Station about 10 kilometres from the Bangladesh border, said streams of people had arrived since Tuesday.

“People who say they are from Bangladesh and want to return home have been coming here since yesterday,” Pati told AFP.

‘Holding centre’

Pati said that the process had “been peaceful and smooth so far”, and they received about 200 people on Tuesday and 40 people early Wednesday.

“While we verify their identities and complete the necessary paperwork, all of them are in a holding centre,” he said, noting they will be handed to India’s border security force and sent to Bangladesh.

“The local administration is catering to all their needs including food, water and lodging,” Pati added.

On Tuesday, Home Minister Amit Shah announced the formation of a special committee on demographic change.

“Illegal migration and other reasons for unnatural demography change are a big challenge for any country’s present and future,” Shah said in a speech.

“Demographic change is a serious issue linked not only to our sovereignty but also to national security, law and order (and) profound changes in social structure,” Shah added.

Top BJP members have previously referred to Bangladeshi migrants as “termites” and “infiltrators”.

Critics say BJP’s rhetoric and policies have added to the unease and marginalisation of India’s estimated 200 million Muslims, accusing the party of conflating religious identity with illegal migration.

The West Bengal centres have drawn particular concern because of the state’s porous border with Bangladesh and its long history of migration.

Relations between India and Muslim-majority Bangladesh soured after a 2024 revolution in Dhaka ended the autocratic rule of then-prime minister Sheikh Hasina, an ally of New Delhi who subsequently fled to India.

The detention order’s apparent inclusion of Rohingya refugees — a mainly Muslim group who fled Myanmar during a brutal military crackdown in 2017 — has also drawn criticism.