Hindu vigilante groups disrupted Christmas mass in parts of India, including in Mr Modi's core territory ahead of local elections in the coming months.

Hardline Hindu outfits affiliated to Mr Modi's party have repeatedly accused the MoC of leading religious conversion programmes under the guise of charity by offering poor Hindus and tribal communities money, free education and shelter.

"Shocked to hear that (at) Christmas, Union Ministry FROZE ALL BANK ACCOUNTS of Mother Teresa's Missionaries of Charity in India!" Mamata Banerjee, the state's chief minister, wrote in a tweet.

"Their 22,000 patients & employees have been left without food & medicines. While the law is paramount, humanitarian efforts must not be compromised," Mr Banerjee, an opposition leader and vocal critic of the Modi government, said.

Nobel-laureate Mother Teresa, a Roman Catholic nun who died in 1997, founded the Missionaries of Charity in 1950.

Headquartered in the eastern state of West Bengal, the MoC has more than 3,000 nuns worldwide who run hospices, community kitchens, schools, leper colonies and homes for abandoned children.

Officials at MoC were not immediately available for comment, while the federal home ministry said the government will issue a statement once an initial inquiry is completed.

"I urge the press to not mix financial irregularities of a charity group with religious sentiments...the decision to freeze accounts has nothing to do with Christianity," an official said, requesting anonymity as he is not authorised to speak to the media.

Vicar General Dominic Gomes of the Archdiocese of Calcutta said the freeze of the West Bengal accounts was "a cruel Christmas gift to the poorest of the poor".

Religious conversions?

Since Mr Modi came to power in 2014, right-wing Hindu groups have consolidated their position across states and launched small-scale attacks on religious minorities, saying their action is to prevent religious conversions.

Christians and other critics say the justification of preventing conversions is false and note Christians represent only 2.3% of India's 1.37 billion people, while Hindus are the overwhelming majority.

The Hindu newspaper on Monday reported disruption of Christmas celebrations at the weekend and last week, including the vandalising of a life-size statue of Jesus Christ at Ambala in Haryana, a northern state governed by Mr Modi's nationalist Bharatiya Janata Party (BJP).

It also reported activists burnt a model of Santa Claus and chanted slogans against Christmas celebrations and religious conversions on Saturday outside a church in Varanasi, Modi's parliamentary constituency and Hinduism's holiest city.

Anoop Shramik, a social activist in Varanasi, told Reuters he saw about two dozen people burning the Santa Claus.

On Saturday, Christmas celebrations were also disrupted in Silchar, eastern Assam, after men, claiming to be members of Bajrang Dal — a right-wing group with close ties to BJP, forced their way into a church, NDTV, a local news channel reported.

Contacted by telephone, the federal and state governments declined to comment on the protests.

Several Indian states have passed or are considering anti-conversion laws that challenge freedom of belief and related rights that the Indian constitution guarantees to minorities.

Elias Vaz, national vice-president of the All India Catholic Union, condemned the latest incidents.

"The strength of India is in its diversity and the people who have done this at Christmas are the real anti-nationals," Mr Vaz said.