UNESCO warned Turkey against turning Hagia Sophia into a mosque, calling for dialogue, a UNESCO spokeswoman told AFP.
The Hagia Sophia is inscribed as a UNESCO World Heritage site.
"This inscription entails a number of commitments and legal obligations," the UNESCO spokeswoman noted.
"Thus, a state must ensure that no modification affects the exceptional universal value of the property inscribed on its territory," she said.
According to her, any modification requires prior notification to UNESCO and possibly examination by its World Heritage Committee.