The prayers were held nearly two weeks after President Erdogan announced his controversial decision to open the 1,500-year-old museum to Muslim worship, converting it into a mosque.

The announcement was made after a Turkish court ruled that the conversion of the monument to a museum initially in 1930s was illegal.

Erdogan was accompanied by several of his top officials and hundreds of worshippers.

Erdogan’s decision of converting the UNESCO World Heritage site has been condemned worldwide.

The monument was built as a cathedral during the reign of Byzantine emperor Justinian I in 537 but was converted into a mosque after the Ottoman conquest of Constantinople in 1453.

It was designated a museum in a key reform of the post-Ottoman authorities under the modern republic's founder Mustafa Kemal Ataturk.

Erdogan had said it had been a "very big mistake" to convert it into a museum.

The United States, the European Union, Russia and various church leaders expressed concern at  Erdogan’s decision while Greece branded the move an "open provocation to the civilised world".

UNESCO said it deeply regretted Turkey's decision, which was "taken without prior dialogue". However, Erdogan said called it Turkey's "historical and sovereign right".