The Delhi police had been tracking mobile phone data to find those who had attended the event, or were in its vicinity.

The gathering, attended by some 9,000 people, has led to a number of Covid-19 infections despite the Indian government’s advice on social distancing.

India's home ministry said 960 foreigners have been blacklisted and their visas cancelled for their involvement in Tablighi Jamaat activities while on tourist visas.

The authorities said the foreigners had misused their tourist visas by participating in religious activities.

Legal proceedings would be initiated against workers under Section 14 of the Foreigners Act, which involves misuse of visas.