The Russian-controlled branch of the Orthodox Church in Ukraine said Tuesday that it would not participate in the establishment of a unified church there as Kiev seeks to cut spiritual ties with Moscow.
The announcement came after a planned meeting between top pro-Moscow clerics and President Petro Poroshenko fell through.
In a historic decision last month, Ecumenical Patriarch Bartholomew I, considered the spiritual leader of Orthodox Christians worldwide, agreed to recognise the Ukrainian Orthodox Church's independence from the Moscow Patriarchate.
The decision sparked rage in Moscow and prompted the Russian Orthodox Church to cut all ties with the Istanbul-based Ecumenical Patriarchate.
The Orthodox church in Ukraine is divided between a branch whose clerics pledge loyalty to Moscow and one overseen by the Kiev-based Patriarch Filaret that Moscow does not recognise.
The split deepened after Russia annexed Crimea and a separatist uprising broke out in eastern Ukraine, a conflict that has claimed more than 10,000 lives since 2014.
On Tuesday, the branch loyal to Moscow said that granting the Ukrainian church independence was an "artificial process that has been imposed from outside" and would only deepen divisions.
"Joining this process is impossible," the Ukrainian Orthodox Church of the Moscow Patriarchate said in a statement.
The Moscow-affiliated branch added that it was breaking communion with the Istanbul-based Ecumenical Patriarchate.
Its top clerics had met at Kiev's Pechersk Lavra monastery, Ukraine's most important Orthodox shrine.
Poroshenko was to have met with them but declined to do so there, though spokesman Svyatoslav Tsegolko said the president was prepared to attend a meeting elsewhere.
Tsegolko accused Moscow of seeking to "disrupt the process of creating" a unified church in Ukraine.
"An absolute majority of citizens of our state support this process," he said on Facebook.
"So going against the will of your own people is obviously a path to nowhere."
Patriarch Filaret, the 89-year-old head of the Ukrainian Orthodox Church of the Kiev Patriarchate, has said he was prepared to lead a unified Ukrainian Church.