Ukrainian media outlets on Friday welcomed what they said was a "serious blow" to Moscow after a historic decision by the Ecumenical Patriarchate to recognise the independence of the Ukrainian Orthodox Church.
But Russian media condemned the "legalisation of a schism" by the Istanbul-based Ecumenical Patriarchate.
The decision, which ends 332 years of the Moscow Patriarch's overseeing Orthodox churches in Ukraine, "will have a historic... significance not just for our country but also for Moscow," wrote Ukrainian daily Den.
The Ukrainian Church is currently split into three bodies, one technically overseen by the Patriarch of Moscow, a fact the Kiev government considers unacceptable given its ongoing war with Russia-backed rebels in the east.
The position of the Russian Orthodox Church in the world is "noticeably shaken," while the country itself has suffered a "serious blow," Den wrote.
Ukrainian news site Glavkom said the "ball is in the Ukrainians' court" to agree as quickly as possible on unifying its currently split church and selecting a new patriarch to formalise the move.
The Segodnya newspaper stressed that the Patriarchate of Constantinople had warned all sides against any seizures of Church property, while the Moscow Church has voiced fears that sacred sites it has historically used will be taken over.
"The Synod in Istanbul has legalised Kiev's 'schismatics,'" was the headline in Russian daily Nezavisimaya Gazeta.
It quoted Metropolitan Alexander of Pereyaslav-Khmelnitsky of the Moscow-led church in Ukraine as saying it "faces the risk of priests fleeing" to the new independent church.
"Constantinople has grabbed Kiev from Moscow," wrote Russian business daily Kommersant, calling it a "historic decision."
"Something frightening will start," warned government newspaper Rossiiskaya Gazeta.
"We are just half a step away from some extremely dramatic consequences, to put it mildly," Russian Orthodox Church spokesman Vladimir Legoida told Russian media on Thursday.
One of the most "sensitive questions" is "what will happen to the existing Orthodox churches in Ukraine," RBK business daily wrote, saying Moscow could have to hand over some of its buildings.
As of the start of 2018, the Moscow-loyal Ukrainian Orthodox Church had jurisdiction over more than twice as many churches in Ukraine as the Orthodox Church led by the Patriarch of Kiev, according to Kiev's official data.
Russian deacon and religious observer Andrei Kurayev, who is known for his reformist views, predicted "the worst possible reaction" from the Russian Orthodox Church in comments to Moskovsky Komsomolets tabloid.
"Now the militant hysterics will begin, saying we'll fight for our churches down to the last Ukrainian," he said.