Turkey's top court considered Thursday whether Istanbul's emblematic landmark and former cathedral Hagia Sophia can be redesignated as a mosque, a ruling which could inflame tensions with the West.
The Council of State was looking at a case brought by a Turkish NGO, the Association for the Protection of Historic Monuments and the Environment, during a short hearing.
It will announce its decision on the fate of the UNESCO World Heritage site within 15 days, state broadcaster TRT reported.
The sixth-century edifice -- a magnet for tourists worldwide with its stunning architecture -- has been a museum since 1935, open to believers of all faiths.
Despite occasional protests outside the site by Islamic groups, often shouting, "Let the chains break and open Hagia Sophia" for Muslim prayers, authorities have so far kept the building as a museum.
Hagia Sophia was first constructed as a cathedral in the Christian Byzantine Empire in the sixth century but was converted into a mosque after the Ottoman conquest of Constantinople in 1453.
Transforming it into a museum was a key reform of the post-Ottoman authorities under the modern republic's founder Mustafa Kemal Ataturk.
But calls for it to serve again as a mosque have sparked anger among Christians and tensions between historic foes and uneasy NATO allies Turkey and Greece.
Since 2005, there have been several attempts to change the building's status. In 2018, the Constitutional Court rejected one application.
During the hearing Thursday, the prosecutor called for the latest case to be dismissed, arguing the decision to alter the Hagia Sophia's status "is a matter for the Council of Ministers and the Presidency," the official Anadolu news agency said.
President Recep Tayyip Erdogan however said last month the decision was for Turkey's highest administrative court -- known as the Danistay -- adding: "The necessary steps will be taken following the verdict."
But Erdogan also said last year it had been a "very big mistake" to convert the Hagia Sophia into a museum.
"The Danistay decision will likely be a political one. Whatever the outcome, it will be a result of the government's deliberation," said Asli Aydintasbas, fellow at the European Council on Foreign Relations.
But she said the government will weigh several issues, including relations with Greece, Europe and with the US where "religion is an important matter".
Anthony Skinner of the risk assessment firm Verisk Maplecroft said converting Hagia Sophia into a mosque would "kill at least two birds with one stone" for Erdogan -- he would cater to his Islamic and nationalist base, and sustain if not exacerbate tensions with Greece, while seeking to cast Turkey as a formidable power.
"Erdogan could not find a more high-profile and potent symbol than Hagia Sophia to achieve all these goals at once," Skinner told AFP.
The Turkish leader has in recent years placed great emphasis on the battles which resulted in the defeat of Byzantium by the Ottomans, with lavish celebrations held every year to mark the conquest.
Muslim clerics have occasionally recited prayers in the museum on key anniversaries or religious holidays.
Greece closely follows what happens to the Byzantine heritage in Turkey and is sensitive to the issue as it sees itself as the modern successor to Orthodox Christian Byzantium.
Greek Culture Minister Lina Mendoni, who sent a letter of protest to UNESCO last week, said the move "rekindles national and religious fanaticism" and is an attempt to "diminish the monument's global radiance".
She accused Turkey of using the monument "to serve internal political interests," arguing that only UNESCO had the authority to change Hagia Sophia's status.
US Secretary of State Mike Pompeo on Wednesday urged Turkey to keep Hagia Sophia as a museum, and to ensure it remains accessible to all.
Turks are divided over its status.
Istanbul shoemaker Mahmut Karagoz, 55, said he dreams he can one day pray under the dome of Hagia Sophia.
"It is a legacy by our Ottoman ancestors. I hope our prayers will be heard, this nostalgia must come to an end," he told AFP.
However economics student Sena Yildiz said she believes Hagia Sophia should stay as a museum.
"It is an important place for Muslims, but also for Christians and for all those who love history," she said.
© Agence France-Presse