Orthodox Church leaders from numerous countries on Tuesday called for unity and raised fears of further discord after the Moscow branch announced it would break ties with the Istanbul-based Ecumenical Patriarchate, in what has been described as one of the gravest crises in the church's history.
The rupture on Monday came after the Istanbul-based clerics agreed to launch the process of recognising the independence of the Ukrainian Church, a move Russia has long campaigned against.
Constantinople's decision last week ended more than 300 years of Moscow's control over Orthodox churches in Ukraine and affects millions of believers in Russia and Ukraine.
While the Patriarch of Moscow up to now has formally overseen Orthodox churches in Ukraine, the country has two other Orthodox authorities which have splintered off without being recognised by Constantinople -- until last week.
The religious split comes amid deep political tensions, with Ukraine opposing Russia's 2014 annexation of its Crimea peninsula and fighting a Moscow-backed uprising in its east in which more than 10,000 people have been killed.
The Russian Orthodox Church's head, Patriarch Kirill, is seen as a close ally of President Vladimir Putin.
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Presidential spokesman Dmitry Peskov said Tuesday that the Kremlin was watching developments "very carefully and with a great deal of worry".
Ukrainian President Petro Poroshenko meanwhile said the Russian Orthodox Church was following the Kremlin down a path of self-imposed isolation.
"Just as Russia opposed itself to the entire world community with its aggressive imperial policy, now the Russian Church is on the path of self-isolation and conflict with the world Orthodoxy," he wrote on his Facebook page.
The Ukrainian president and lawmakers have backed independence for the country's divided Orthodox Church and see it as striking a blow against Moscow's influence in Ukraine.
While the conflict grew out of the turbulent relations between Ukraine and Russia, a complete breach between the churches in Moscow and Turkey could threaten the integrity of the Orthodox Church as a whole, which has some 250 million believers around the world.
The various Orthodox churches are already divided on the issue.
Serbian Patriarch Irinej said in an interview with a local news site: "We don't think in terms of 'for' and 'against'."
"We are for the unity of the Church, harmony, responsibility for canonical order, and against everything that divides and leads to the risk of schism."