NEW DELHI: 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 centers for undocumented Bangladeshi migrants and Rohingya refugees.

Prime Minister Narendra Modi’s Hindu-nationalist Bharatiya Janata Party (BJP) swept to power in West Bengal state in early May with a hard-line 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 centers” for “apprehended foreigners,” singling out both Bangladeshis and Rohingya.

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