The police in Warwickshire, United Kingdom, arrested 55 people on Sunday after a large group of Sikh men forcibly entered a gurdwara in the town of Leamington Spa. According to local news reports, the men, possibly belonging to a militant Sikh group in Birmingham, were trying to stop an interfaith wedding.

While some reported that the group was carrying “sharp blades”, it is not uncommon for Sikhs to carry a knife of this kind known as the kirpan as part of their religious accoutrement. The protest went on for more than eight hours and police forces had to surround the gurdwara, while some officers went inside for negotiations.

A former treasurer at the gurdwara told BBC that a mixed-faith marriage was due to take place there that day, and that local Sikh groups had been objecting to such unions “for several years”. The police said they are treating the incident as one of “aggravated trespass”.

This is not the first time mixed-faith marriages have been opposed by Sikh groups in the UK. A BBC report from 2013 document several such cases, attributing the protests to the rise in the number of these marriages.