There are fears that, with a full-blown dispute between Church authorities, congregations could be shut out of certain churches.
President Poroshenko accuses the Kremlin of trying to foment a religious war, and he has warned that Russian agents could try to seize church property.
The Moscow Patriarchate says its worshippers should no longer attend any services conducted by clergy loyal to Constantinople. From now on it will also boycott joint Orthodox Church ceremonies.
Mr Putin’s spokesman Dmitry Peskov said the Kremlin would defend “the interests of Russians and Russian speakers and the interests of the Orthodox”, but only by using “political and diplomatic measures”.
Russia also said it had to protect ethnic Russians ahead of its military intervention in Ukraine in 2014.
So there is potential for serious conflict, not least because Ukraine’s Orthodox believers are divided among three Churches: the Ukrainian Orthodox Church (Moscow Patriarchate), the Orthodox Church of the Kiev Patriarchate and the small Ukrainian Autocephalous Orthodox Church (UAOC).
— Kendall Harmon (@KendallHarmon6) October 17, 2018