Indian police are probing a charity started by Mother Teresa, officials said Tuesday, in the latest example of growing pressure on Christians under Prime Minister Narendra Modi's Hindu nationalist government.

Authorities in the western state of Gujarat told AFP they were investigating whether the Missionaries of Charity forced girls in its shelter home there to wear a cross and read the Bible. 

Modi's home state is one of several in Hindu-majority India where vaguely worded rules against "forceful conversion" have been put in place, or more strictly enforced, in recent years.

District social officer Mayank Trivedi told AFP that his complaint to the police was based on a report by child welfare authorities and other district officials. 

According to the complaint, 13 Bibles were found in the library of the institute and girls staying there were forced to read the religious text.

The Missionaries of Charity, founded in 1950 by the late Mother Teresa -- a Roman Catholic nun who lived and worked in Kolkata for most of her life and won the Nobel Peace Prize -- denied the allegations.

Activists say that religious minorities in India have faced increased levels of discrimination and violence since Modi's Hindu nationalist Bharatiya Janata Party (BJP) came to power in 2014.

In 2020, the US Commission on International Religious Freedom listed India as a "country of particular concern" for the first time since 2004. 

Modi's government rejects having a radical "Hindutva" (Hindu hegemony) agenda and insists that people of all religions have equal rights.

Activists say there have been more than 300 anti-Christian incidents this year alone. 

Last week, a Hindu mob of 200 to 300 people barged into a Christian school in Madhya Pradesh while students were taking their exams and pelted stones at the building, the school's principal said.

"We moved the children from the auditorium to another wing of the school. We kept them on the first floor and gave them extra time to finish the exam. But the students couldn't write, they were crying and shivering," Brother Anthony Tynumkal, principal of St Joseph School, told AFP.