Reuters reported that Turkish President Recep Tayyip Erdogan signed a decree converting the Hagia Sophia to a mosque, after the decision of the Supreme Administrative Court in Turkey to cancel the status of the Hagia Sophia as a museum, amid international criticism of the move.

Earlier today, the Supreme Court issued a ruling revoking the Turkish Cabinet’s decision in 1934 to convert the Hagia Sophia Mosque into a museum.

Turkish presidential spokesman Ibrahim Qalan said that opening the Hagia Sophia for worship does not detract from his global historical identity, indicating that more people can visit him.

For its part, the United Nations Educational, Scientific and Cultural Organization (UNESCO) called on Turkey to dialogue before any decision is likely to "undermine the global value" of this global monument.

In response to a question to Agence France-Presse on Friday, UNESCO-based Paris stressed by e-mail that "Hagia Sophia was on the World Heritage List of Humanity as a museum, which entailed a number of legal obligations."

"Therefore, the state must ensure that any amendment does not adversely affect the global value of the sites listed on the UNESCO list. Any amendment requires a prior notification to UNESCO from the country concerned and then an examination by the World Heritage Committee."

UNESCO expressed "these concerns to Turkey in several messages," as well as in a message sent to the Turkish representative at UNESCO Thursday evening, calling "the Turkish authorities to start a dialogue before taking any decision that might undermine the global value of the site."

Russian officials and the Russian Orthodox Church have urged Turkey to be cautious about efforts to return the Hagia Sophia Museum in Istanbul to a mosque, as it has a "sacred value" for the Russians.

The Church of Hagia Sophia was converted into a mosque with the Ottomans conquering Constantinople in 1453, and then it became a museum in 1935 by the Turkish President Mustafa Kemal Ataturk, with the aim of "dedicating him to humanity."

And Turkish President Recep Tayyip Erdogan has previously proposed returning the UNESCO World Heritage Site to a mosque again.

Erdogan last week described criticism of a possible diversion of this historical impact as an attack on Turkish sovereignty.