Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Turkey Battles Criticism Over Decision to Turn Hagia Sophia Into Mosque Dorian Jones ISTANBUL - This Friday, Islamic prayers are due to be held in Istanbul's iconic Hagia Sophia for the first time since Turkey's government decided to re-convert the ancient cathedral into a mosque. Russia has stepped in, with Moscow voicing concern to Ankara over the fate of the historic building, including its world-famous Christian mosaics. A spokesman for Turkish President Recep Tayyip Erdogan, who has spearheaded the push to change the status of the monument from museum to mosque, earlier said Christian mosaics would be concealed with curtains or lighting during Friday prayers. Within days of an Istanbul court revoking the Hagia Sophia's museum status - paving the way to its conversion to a mosque - Russian president Vladimir Putin was on the phone to President Erdogan seeking assurances over the state of the mosaics. Russian Orthodox leaders have also expressed concerns about building's conversion, which they describe as a threat to Christianity. The 6th-century Byzantine cathedral is not only famous as an architectural marvel, but also for the large mosaics depicting Christ, the Virgin Mary, and Byzantium rulers decorating the building's massive walls ceilings. 'A major monument' for Christians Russia's Orthodox Church is a powerful force within Russian society. "These images are very important for Christianity because it was a major monument for Christian people," said professor Zeynep Ahunbay, who spent 25 years working on the Hagia Sophia's restoration and preservation. "All possible steps must be taken to prevent damage that could be caused by the hasty change in the status of the world-renowned museum," read a statement this month by the Russian parliament the State Duma. .