The head of Russia's Orthodox Church has blamed Orthodox leaders in Istanbul for causing the biggest dispute to face the religion in hundreds of years.
Patriarch Kirill on October 19 blasted church authorities -- known as the Ecumenical Patriarchate of Constantinople -- as "schismatic" for a decision earlier this month moving to grant independence to the Ukrainian Orthodox Church.
The Russian Orthodox Church responded by breaking ties with the Constantinople Patriarchate, widely recognized as the spiritual authority of Orthodoxy.
"The Constantinople Patriarchate identified itself with schismatics," Patriarch Kirill told a conference in Moscow.
"Uncanonically, violating all rules, it invaded our jurisdiction and forgave schismatics," he added.
Ukraine has three Orthodox churches: the Ukrainian Orthodox Church of the Moscow Patriarchate, the Ukrainian Orthodox Church of the Kyiv Patriarchate, and the Ukrainian Autocephalous Orthodox Church.
The Moscow Patriarchate, which has the most believers in Ukraine, remains loyal to the Russian Orthodox Church. The Kyiv Patriarchate declared independence from the Russian church in 1992, but that has never been recognized by the Ecumenical Patriarchate of Constantinople.
Earlier this month, however, Patriarch Bartholomew, who is considered the "first among equals" leader among Orthodox leaders, endorsed the Kyiv Patriarchate's request for independence from Moscow.The Kyiv Patriarchate has not yet received the formal, final blessing to be autocephalous, or independent.
The move from Bartholomew prompted angry words from not only Russian church leaders, but also government officials.
On October 15, the Russian church announced it had decided to end its relationship with the Constantinople Patriarchate.
Several Orthodox churches in former Soviet republics, many of which are under the direct jurisdiction of the Russian Orthodox Church, also cut ties with the Constantinople Patriarchate.
Bartholomew's move has added to tensions between Kyiv and Moscow, already high since Russia's 2014 seizure of Crimea and the war in eastern Ukraine between government forces and Russia-backed separatists.
Reacting to the Russian Orthodox Church's announcement, the press secretary of the Kyiv Patriarchate said, “Patriarch Kirill has personally been an architect of the schism in the Ukrainian church since 1991" and that his conduct has "pulled all of Orthodox Christianity into conflict."
There are an estimated 300 million Orthodox Christians worldwide, with the Russian church claiming to have the largest number of believers.
In a statement issued October 19, the United States signaled support for the push for independence by the Kyiv Patriarchate.
"The United States reiterates its strong support for religious freedom and the freedom of members of religious groups, including Ukraine’s Orthodox community, to govern their religion according to their beliefs, free of outside interference," Secretary of State Mike Pompeo said.
"Tolerance, restraint, and understanding are key to ensuring that people with different religious affiliations can live and prosper together in peace. We urge Church and government officials to actively promote these values in connection with the move towards the establishment of an autocephalous Ukrainian Orthodox Church," he said.
With reporting by RFE/RL's Belarus Service, AFP, AP, and The National Catholic Register