According to police reports, the party was held on the top floor of a residence on Melantrichova street in central Prague. A total of 63 guests were found inside.
"Yesterday evening, Prague police officers carried out an intervention in a house in Melantrichova Street, where, according to our sources, several dozen people were attending a party," police spokesperson Jan Rybanský told iDnes.cz.
"Police found 63 people at the location, 59 of whom were reported violating current government regulations," he added. The four people not violating government regulations may have been residents of the apartment.
According to Novinky.cz, many of the participants were foreigners. Three guests were not able to provide valid documents, and were handed over to Foreign Police.
Another five participants were found to be in possession of marijuana, and have had misdemeanor charges filed against them.
Seven people were identified as organizers of the party, and detained by police. Charges brought against them should be revealed later today.