Russian Orthodox Church vents its fury at John Paul's visit to western Ukraine

A rickety wooden plank over a big hole in the ground is for the moment the only way into St George's Cathedral in Lviv, western Ukraine, where Pope John Paul II will worship at the end of the month. Builders are working frantically in the rain with blowtorches to complete the roof of a nearby building where the Pope will sleep.

The visit has already produced fury in Moscow where Aleksei II, the Patriarch and head of the Russian Orthodox Church, is angrily accusing the Vatican of launching an invasion. He claims his priests are being beaten and his parishioners "hounded" from their churches. He says he will refuse to meet John Paul II when he visits Ukraine on 23-27 June unless the Vatican stops the persecution and ceases its expansion into lands traditionally Orthodox.

The rhetoric coming from the Russian Orthodox hierarchy has all the venom of one of Ian Paisley's diatribes against the Papacy. The anger has its origins in the rebirth of the Greek Catholic Church, illegal under the Soviet Union, in western Ukraine where it has five million members. The Greek Catholics, Orthodox in all but their allegiance to Rome, have taken over properties they say once belonged to them. Aleksei II said this week: "The wounds are still bleeding that were inflicted at the beginning of the 1990s when Greek Catholics violently seized Orthodox churches." Nor is he alone in his opposition to the Pope's visit.

A thousand marchers, accompanied by Cossacks, rallied in the most ancient monastery in Kiev, the Ukrainian capital, last month, holding up banners reading "The Pope ­ persona non grata" and "Orthodox Ukraine has not yet died".

In western Ukraine hundreds of Orthodox churches changed sides or were taken over. Priests and parishes fought, sometimes physically, over ownership of church property. The Orthodox Archbishop of Lviv claims that, when he sought to enter a church in the village of Urizh, Greek Catholics tried to throw him down stairs and ripped his surplice.

The Greek Catholics say this is all exaggerated. "The claim that there are many conflicts over property continuing today simply is not true," says Andriy Nahirnyak, a young Greek Catholic priest who is helping to organise the Pope's visit. "There are only two such disputes still going on in Lviv."

Aleksei II claims, however, that "recently Greek Catholics attempted to destroy an Orthodox church in Lviv to clear the way for the Pope's procession".

The Vatican is treading warily in this minefield of conflicting loyalties. For some Ukrainians in Lviv, the heart of Ukrainian nationalism, the dispute between Rome and Moscow is very simple. "It is all a question of independence from Russia," asserts Taras Voznyak, the editor of the cultural magazine Ji in Lviv.

"The Patriarch in Moscow has no more right to protest about the Pope coming to Ukraine than he would have if the Pope went to Britain." This is not quite true. Religious allegiances in Ukraine are extraordinarily confused because, in addition to the Greek Catholics, there are three different Orthodox churches. The largest, followed by 70 per cent of Orthodox believers, gives allegiance to Aleksei II in Russia.

It is the Russian Orthodox Church that now feels persecuted in western Ukraine. "Police officers with machine guns prevented our people from attending vespers," claimed a witness belonging to the Orthodox church owing allegiance to Moscow after a six-year battle for control of a priest's house.

As a Pole, John Paul II should have an acute sense of the nuances of the religious conflict raging in Ukraine just across the border from Poland. Most Ukrainians will welcome the visit because they feel ignored by the rest of the world since their country became independent. Moscow does not like what is happening but, for the moment, there is not much it can do about it.