Bulgarian prosecutors have charged a Muslim religious leader and six others with spreading war propaganda for the Islamic State group.

Deputy Prosecutor General Borislav Sarafov told reporters Wednesday that six men and one woman, including an imam named Ahmed Mussa, were charged with preaching the anti-democratic ideology of the Islamic State group.

Sarafov said they are believed to have operated as an organized criminal group led by the imam, who allegedly had preached surrounded by the Islamic State flags urging his followers to be prepared to fight against Christianity.

Police operations in several cities uncovered a large number of shirts and banners with the logo of the Islamic State. Investigators also found evidence that the detainees helped western Europeans on their way to join the Islamic State group.