The United States Senate Foreign Relations Committee Chairman James Risch (R-Idaho) and ranking member Bob Menendez (D-N.J.) on Friday condemned the decision by Turkish President Recep Tayyip Erdoğan to turn the Hagia Sophia, an Istanbul landmark, back into a mosque.

The UNESCO World Heritage building, which was built as a Christian cathedral during the Byzantine Empire, had served as a place of worship for Greek Orthodox Christians, Roman Catholics and Muslims prior to being converted into a secular museum in the 1930s.

Erdoğan on Friday announced the building’s conversion into a mosque after a local court ruling allowing him to take away the museum status of the building.

“We strongly denounce President Erdoğan’s decision to convert Hagia Sophia from a museum into a mosque. At points in its history, Hagia Sophia served as a place of worship for Muslims and Christians, and for decades has been an extraordinary and welcoming center to people of all faiths,” they said in a joint statement.

The lawmakers called Erdoğan’s move “a deep affront to Christians around the world who look to Hagia Sophia as a shining light and deeply revered holy site.”

“This conversion of its status is unnecessarily divisive at a time when we need more, not fewer, efforts to build bridges between Islam and Christianity,” they said in their official statement.

The senators said they “strongly urge” Erdoğan to reverse his decision and retain Hagia Sophia’s “status as a religiously neutral museum for peoples of all faiths and cultures to visit and celebrate our common world heritage.”