Russian President Vladimir Putin condemned the creation of a Ukrainian Orthodox Church independent of Moscow at his annual press conference on Thursday, saying it violated religious freedoms and drove a wedge between the nations.
Orthodox bishops created the new Ukrainian church at a historic synod in Kyiv on Saturday, ending more than 300 years of Moscow domination. The decision was welcomed by Ukrainian President Petro Poroshenko and the United States.
But Putin slammed the decision as a "blatant breach of religious freedoms".
Also on Thursday, Ukraine's parliament passed a law that obliges the Moscow-backed branch of the country's Orthodox Church to mention its allegiance in its name.
A physical fight broke out in the chamber after the bill passed, and one lawmaker ripped down a poster of a pro-Russia politician.
The Church's creation came after a landmark decision by Istanbul-based Ecumenical Patriarch Bartholomew I to recognize Ukraine's independence from the Russian Orthodox Church.
The ruling in October sparked fury in Moscow, which has overseen the Ukrainian branch of Orthodoxy for the last 332 years. It led the Russian Orthodox Church to cut all ties with the Ecumenical Patriarchate of Constantinople.
Putin on Thursday suggested that Bartholomew's "main motive" was to "subjugate" Ukraine.
"It is also done with the aim of a further split between the peoples of Ukraine and Russia," he said.
Putin also warned the decision would lead to a redistribution of Church property that could be "bloody".