The allegedly coerced religious conversions of more than 50 poor Muslim families in India has been condemned by Islamic leaders, who say the incident — reportedly conducted en masse at a ceremony — threaten to sow fresh discord in the predominantly Hindu country.

Senior Muslim clerics in India called for action following allegations that members of their community living in the slums of Agra, in north India, were lured last week into participating in an event organized by Bajrang Dal, according to the Washington Post. The hardline Hindu nationalist group has ties to Prime Minister Narendra Modi’s Bharatiya Janata Party (BJP).

Separately, police in Uttar Pradesh, the state where last week's event occurred, issued a warning on Sunday to a Hindu nationalist group that had vowed to hold another conversion ceremony on Christmas Day. "No event will be allowed on 25 December, whether it is conversion or anything similar to it," a police official was quoted by the BBC as saying.

A delegation of senior clerics is heading to Agra in the state of Uttar Pradesh to investigate the conversions, the Times of India reported on Sunday. "This is a serious matter, and we don't want to escalate the crisis, but at the same time [we] condemn the forcible conversions," Maulana Khalilur Rahman Noorie, general secretary of the Association of Imams, told the newspaper.

Muslims who participated in the ceremony alleged that they were lured into participating following assurances by the organizers that they would receive government welfare assistance, the Washington Post reported.

Religious conversions have become a flashpoint of criticism for the BJP since Modi took office in May. Muslim groups and opposition parties accuse organizations tied to the BJP of trying to undermine the nation's secular foundations. But organizers of the ceremonies insist that they are voluntary. "We have been doing this every year for the past 10 years," Yogi Adityanath, a member of parliament from the BJP, told Reuters.

India's 1.2 billion people are predominantly Hindu. But the country also has some 160 million Muslims and a small proportion of Christians.

The constitution grants equal rights to everyone, but critics say that right-wing Hindu nationalist groups have become more assertive since the BJP came to power in a landslide victory this year. "These conversions are just the beginning," Mulayam Singh Yadav, a prominent leader of a regional political party in U.P., told Reuters. "If this spreads to other parts of the country, there can be riots."

Last week, a government minister apologized for making derogatory remarks about non-Hindus. On Friday, Sakshi Maharaj, a BJP member of parliament from U.P., withdrew his remarks that Nathuram Godse, a Hindu nationalist who shot independence leader Mahatma Gandhi, was a patriot. Maharaj's comment touched off an uproar in parliament, and opposition MPs refused to allow any business until he retracted.

The BJP denies any bias against minorities, but Modi’s critics say that hardliners within his party are pursuing a divisive agenda.

Al Jazeera and Reuters