Turkish President Recep Tayyip Erdogan attended the first prayers in Istanbul's Hagia Sophia on Friday, after it was converted from the world heritage site back into a mosque.
Some 500 people were allowed inside the mosque for the service with thousands more praying outside the complex.
Footage shows Erdogan with a face mask arriving at Hagia Sophia surrounded by officials and security staff.
On July 10, Turkey's Council of State ruled the landmark to be turned back into a place of worship, overturning a 1934 decree which made the mosque a museum.
UNESCO released a statement following the decision, expressing concerns about the impact it may have on the universal value of the site and called on Turkish authorities «to engage in dialogue» on the matter.