Turkey continues to encroach on spiritual and cultural values, the Catholicos of the Great House of Cilicia Aram I wrote on his Facebook.
His remarks came following the Turkish decision to convert Hagia Sophia into a mosque.
According to him, in recent days, church leaders, as well as the international community, have called on Turkey not to resort to this step.
"Turkey, at the initiative of its president, actually continues its behavior by infringing on spiritual and cultural values, ignoring the principles established by international law, and falsifying history," he added. "With this decision, Turkey deliberately strikes at the coexistence of Christian-Islamic mutual respect and trust."
Turkish President Recep Tayyip Erdogan signed a decree Friday on converting Hagia Sophia into a mosque, Reuters reported.
Erdogan shared on Twitter a copy of the decree he had signed according to which the decision had been taken to hand control of 'the Ayasofya Mosque, as it is known in Turkish, to the country’s religious directorate and reopen it for worship.'
A Turkish top administrative court ruled Friday in favor of a proposal to turn the Hagia Sophia museum back into a mosque.
According to Anadolu Agency, thus, the court annulled a 1934 presidential decree converting Hagia Sophia into a museum.
The Hagia Sophia was the Roman Empire's first Christian cathedral: it was converted from a Greek Orthodox cathedral to a mosque in 1453 and then became a museum in 1935.
UNESCO has earlier warned Turkey against turning Hagia Sophia into a mosque, calling for dialogue.
The Hagia Sophia is inscribed as a UNESCO World Heritage site.