Istanbul’s Hagia Sophia – a Byzantine-era cathedral that now serves as a museum – could be reconverted into a mosque, Recep Tayyip Erdogan, the Turkish president, has said.
Mr Erdogan made the comments during a television interview late on Sunday ahead of Turkey’s March 31 local elections.
The former Byzantine cathedral had previously been converted into a mosque after the Ottoman conquest of the city, then-known as Constantinople, in 1453.
Turkey’s secular founder, Mustafa Kemal Atatürk, turned the structure into a museum in 1935 that attracts millions of tourists each year.
There have however, been increasing calls for the government to convert the symbolic structure back into a mosque, especially following reports that the gunman who killed Muslim worshippers in New Zealand left a manifesto saying the Hagia Sophia would be "free of minarets."
Mr Erdogan himself recited prayers inside the Hagia Sophia last year.
The suggestion that Hagia Sophia could be turned into a mosque provoked anger in Greece.
"It is not only a great temple of Christendom – the largest for many centuries – it also belongs to humanity. It has been recognized by UNESCO as part of our global cultural heritage," George Katrougalos, the Greek foreign minister, said.
"So any questioning of this status is not just an insult to the sentiments of Christians, it is an insult to the international community and international law."
"We want to hope that the correct statements of March 16 by the Turkish leadership will be valid and there will be no change of this status," he added, in reference to a speech by Mr Erdogan when he ruled out its conversation into a mosque.
Meanwhile, on Monday Greek Prime Minister Alexis Tsipras said Turkish jets buzzed his helicopter as he was flying to a Greek island to mark the anniversary of the 1821 uprising against Ottoman rule, but Turkey said there was no attempt to intercept his flight.