The believers were holding prayers in the house of one Pelagie Nyiranduhura, 36, in Rwimpongo II Village, Rwintashya Cell of Rukumberi Sector.
The gathering is prohibited under the national directives meant to fight further spread of the COVID-19.
Chief Inspector of Police (CIP) Hamdun Twizeyimana, the Police spokesperson for the Eastern region, said the violators were in an overnight prayer.
"The illegal overnight prayers caused noise pollution in the neighbourhood, which prompted the residents to call authorities for intervention at about 5 am," said CIP Twizeyimana.
"Police and local leaders first found 26 people from different religious denominations, in the same house and took them to the sector offices, but residents called again later after more people came in that morning for prayers, which were supposed to last for three days. They caught other ten people in the same house. All the violators were educated on the pandemic of the COVID-19 and prevention measures, but were also fined for the violation," he added.
At least 10 of the violators are members of ADEPR church, six methodists, five from the Catholic Church and others from the Anglican Church.
They came from Rukumbeli, Zaza and Mugesera sectors in Ngoma District.
Other came from Rwamagara and Bugesera districts.
"They came from different districts, congested in a small room praying, no one was wearing a facemask and no hand washing. One person infected with COVID-19 could have easily infected everyone there," said CIP Twizeyimana.
"As we have seen in daily reports on COVID-19 infections by the Ministry of Health, positive cases have been reported in most parts of the country and such unnecessary movements and prohibited gatherings could easily spread the pandemic and affect national response efforts."
The spokesperson thanked the residents for the neighbourbood watch and called for continued partnership and information sharing on any unlawful acts.