Egypt's state religious authority has banned the use of loud speakers in mosques beyond the call to prayer (Azan) and Friday afternoon sermons, an official statement said.
The ministry of religious endowments (Awqaf) also warned in Friday's statement that violators could face salary deductions or transfer.
Awqaf asked its employees in different governorates to provide the names of those responsible for mosque property and its speakers within 10 days.
Millions of Muslim Egyptians, men and women, attend Friday prayers in mosques and listen to the recently standardised sermons by Awqaf-appointed Imams.
Islamic jurisprudence mandates Muslims conduct five sets of daily prayers.
In March, Awqaf placed all non-governmental Islamic cultural institutes and preacher training centres under its direct supervision.
Last year, Awqaf mandated all preachers to acquire a permit before administering sermons on the pulpit, banning all unlicensed preachers.
The ministry also prohibited Friday prayers at small, less-regulated corner mosques known as Zawaya.
President Abdel-Fattah El-Sisi recently called on Al-Azhar to "revolutionise" its religious discourse in order to guide Muslims to a correct understanding of Islam.