The Ecumenical Patriarch of Constantinople has signed a decree of independence for the Orthodox Church of Ukraine.

Patriarch Bartholomew I signed the "Tomos" in Istanbul Saturday, formalizing the Ukrainian church's independence from the Russian Orthodox Church to which it has been tied to since 1686. The move is forcing Ukrainian clerics to pick sides as fighting persists in eastern Ukraine between government forces and Russia-backed rebels.

Last month, Ukrainian Orthodox leaders approved the creation of a new, unified church split from the Moscow Patriarchate and elected Metropolitan Epiphanius to lead it. The Russian church has severed ties with Istanbul, the center of the Orthodox world.

Ukrainian President Petro Poroshenko, who has campaigned for the creation of the new church, met with Turkish President Recep Tayyip Erdogan before the ceremony.