Police in India have detained hundreds of people across several cities for defying a ban on protests against a new citizenship law that opponents say threatens the country’s secular democracy.

Authorities on Thursday disrupted internet and phone services, including in parts of New Delhi, and tightened restrictions on protests in the northeastern border state of Assam, which is where the demonstrations first began last week.

The legislation has provoked anger because it offers a path to citizenship for persecuted minorities from three neighbouring countries – but excludes Muslims.

Critics say it is the latest effort by Prime Minister Narendra Modi’s Hindu nationalist-led government to marginalise India’s 200 million Muslims, and a violation of the country’s secular constitution.

Modi has defended it as a humanitarian gesture.