Eid prayer was held at Istanbul's iconic Hagia Sophia Mosque on Thursday after an 87-year hiatus.
Thousands of worshippers joined the prayer led by Ali Erbaş, head of Turkey's top religious body Diyanet.
Erbaş delivered the Eid sermon holding a sword in his hand, an age-old Ottoman tradition that signifies conquest.
"These holidays are being held during exceptional times that define us, unite our hearts, and reinforce our brotherhood," he said.
He offered special prayers for Palestinians who are facing the onslaught of Israeli forces.
"The attempt of Israel, which does not give up its aggressive attitude even during Ramadan, to occupy the holy city of Jerusalem and our first Qibla, Masjid Al-Aqsa, brings great sorrow and pain to all believers," Erbaş said.
He added that attacking Muslim worshippers "barbarically" violated the sanctity of the holy mosque and the memory of the prophets.
"Our innocent Palestinian brothers and sisters are being forcibly evicted from their homes and subjected to massacres," he said, noting that every holiday will pass with a heavy heart until Palestine and the Al-Aqsa are liberated.
In the past, Hagia Sophia served as a church for 916 years and 86 years as a museum, but most of its existence-1453 to 1934, nearly 500 years-it spent as a mosque, a status it resumed last year.
In 1985, Hagia Sophia was added to the UNESCO World Heritage List.
Besides being a mosque, the Hagia Sophia is also among Turkey's top tourism destinations and remains open for domestic and foreign visitors.
