ATHENS — Compounding Turkish President Recep Tayyip Erdogan’s plan to turn the ancient revered Orthodox Church of Aghia Sophia – now a museum – into a mosque has run into the oversight of Russian President Vladimir Putin.

The Russian government said it expects a “balanced” decision about the cathedral in Constantinople, which the rest of the world outside Greece calls Istanbul, adding that the decision must use guidelines set by UNESCO, the United Nations agency which has designated the church as historic.

“We believe that the monument of Aghia Sophia is extremely important for all mankind in terms of culture and history,” Russian Foreign Ministry spokeswoman Maria Zakharova told Russian journalists.

“Aghia Sophia is a UNESCO World Heritage Site and we believe that any request related to the status of the monument, including its maintenance and accessibility, will comply with the rules set and mandated by the organization,” Zakharova said.

“We expect that any decision on the status of this unique monument will be of a balanced nature, taking into account how sensitive this issue is for the faithful,” she added, said Kathimerini in a report.

Turkey’s highest administrative court heard the case July 2 and is expected to make its decision by July 15 over the site that draws some three million visitors a year but with Greece and critics warning that changing the status could cause a furor and deepen the divide between Christians and Muslims.