Patriarch Bartholomew sent two bishops as representatives to a pro-Western church in Ukraine, a move which was seen as anti-Moscow as it effectively declared the Ukrainian church independent from the Russian branch.
Patriarch Kirill of the Russian Orthodox Church called together a Holy Synod in response on Friday and criticised Bartholomew.
Vladimir Legoida, a Russian Orthodox Church spokesman, said the Holy Synod had decided to suspend its participation in all structures chaired or co-chaired by representatives of the Patriarchate of Constantinople.
Kirill will now no longer mention Bartholomew in his prayers and they will not conduct services together. Kirill takes a similar view to President Putin on Ukraine, that it should be part of greater Russia and that any separation would be negative to that aim.
In Ukraine, there is a split between the pro-Russsia Moscow Patriarchate and the Kyiv Patriarchate, who split from Moscow in 1992 and consider them Kremlin-supporters.
Bartholomew's reach-out was towards the pro-Western, Kyiv branch of the Orthodox church, therefore it was seen as a threat to unity between Moscow and Istanbul, where the Archbishop of Constantinople (now Istanbul) is based.
"Essentially this is a breakdown of relations. To take an example from secular life, the decision is roughly equivalent to cutting diplomatic ties," the Russian Church's Metropolitan Ilarion was quoted by the RIA news agency as saying.
Stay up to date with the latest news stories from a Christian perspective. Sign up to our daily newsletter and receive more stories like this straight to your inbox every morning.
