Authorities in Egypt arrested three men after one of them was allegedly filmed singing and dancing in a mosque, according to the AFP news agency.
The clip later went viral. In the video, the accused man is singing along to what locals call a mahraganat song.
It is a type of electronic music which authorities have labelled inappropriate and therefore forbid their performance.
Critics have condemned human rights record under President Abdel Fattah al-Sisi, including the arrest of several activists under his watch.