"The news that the muezzin Osman Aslan died suddenly of a heart attack on Sunday, August 2, 2020, in the Hagia Sophia, caused a sensation," the message said.
Aslan was one of those who called Muslims from the minarets to pray in Hagia Sophia.
The cathedral was built in 532-537 by order of the Byzantine emperor Justinian I. Hagia Sophia was the largest church in Christianity for about a millennium.
In 1934, Hagia Sophia became a museum. Now the cathedral is on the UNESCO World Heritage List.
Hagia Sophia is visited by millions of tourists every year. According to the Istanbul authorities, 3.7 million tourists visited the monument in 2019 alone.
As we reported before, in Istanbul's Hagia Sophia, the first Friday prayer in 86 years was performed.
"The first Friday prayer in 86 years was performed at the Hagia Sophia Mosque in Istanbul," the message says.