A Turkish court is likely to announce on Friday that the 1934 conversion of Istanbul's Hagia Sophia into a museum was unlawful, two Turkish officials said, paving the way for its restoration as a mosque despite international concerns.
President Tayyip Erdogan has proposed restoring the mosque status of the sixth-century UNESCO World Heritage Site, which was central to both the Christian Byzantine and Muslim Ottoman empires and is now one of the most visited monuments in Turkey.
The prospect of such a move has raised alarm among US, Russian and Greek officials and Christian church leaders ahead of a verdict by Turkey's top administrative court, the Council of State, which held a hearing last Thursday.
At issue is the legality of a decision taken in 1934, a decade after the creation of the modern secular Turkish republic under Mustafa Kemal Ataturk, to turn the ancient building into a museum.
"We expect the decision to be an annulment (and) the verdict to come out on Friday," a senior Turkish official told Reuters.
An official from Erdogan's ruling AK Party, which has Islamist roots, also said the decision "in favour of an annulment" was expected on Friday.
Pro-government columnist Abdulkadir Selvi wrote in the Hurriyet newspaper that the court had already made the annulment ruling and would publish it on Friday.
"This nation has been waiting for 86 years. The court lifted the chain of bans on Hagia Sophia," he wrote.
The association that brought the case said Hagia Sophia was the property of Ottoman Sultan Mehmed II, who in 1453 captured the city, then known as Constantinople, and turned the already 900-year-old Byzantine church into a mosque.
Ecumenical Patriarch Bartholomew, the spiritual head of some 300 million Orthodox Christians worldwide and based in Istanbul, said a conversion would disappoint Christians and "fracture" East and West. The head of Russia's Orthodox Church said it would threaten Christianity.
US Secretary of State Mike Pompeo and Greece have also urged Turkey to maintain the museum status.
But Turkish groups have long campaigned for Hagia Sophia's conversion, saying it would better reflect Turkey's status as an overwhelmingly Muslim country.