MOGADISHU, Somalia — The Shabab, Somalia’s most powerful Islamist insurgent group, outlawed school bells in a southern town on Thursday after deciding that they conflicted with Islam, residents said.

School principals in the town, Jowhar, about 55 miles north of Mogadishu, the capital, had been summoned to a meeting and informed that the bells could no longer be used because they sounded like church bells, according to one principal.

“There was no bell rung in our school today,” said Hamdi, a student at the Kulmis Primary and Secondary School, who asked that her full name not be used out of fear for her safety. “Some teachers were hitting the doors as the period finished. It is really confusing.”

The Shabab also outlawed the observance of internationally recognized days like World AIDS Day, saying that only Islamic festivals could be recognized.