A poster promoting the "Rosary to the Borders" initiative fixed in a Warsaw church

Hundreds of thousands of Polish Catholics are expected to descend Saturday on the country's borders to recite the rosary "to save Poland and the world" from the dangers facing them, organisers say, but others claim the event is aimed at protecting Europe from what they term a Muslim onslaught.

The episcopate insists that the "Rosary to the Borders" is a purely religious initiative, but some Catholics view it as a weapon against "Islamisation."

The date was not chosen at random. October 7 is when Catholics celebrate the Feast of Our Lady of the Rosary, marking the 1571 victory of Christianity over the Ottoman Turks at the Battle of Lepanto.

A victory attributed to the recital of the rosary "that saved Europe from Islamisation", the Solo Dios Basta foundation said on the website of the event it is organising.

Many Poles see Islam as a threat. The conservative government, which enjoys the backing of a sizeable portion of the population, refuses to welcome migrants to Poland, which has very few Muslims of its own.

Twenty-two border dioceses will take part in the event, whose faithful will congregate in some 200 churches for a lecture and mass before travelling to the border to say the rosary.

The goal is to have as many prayer points as possible along the 3,511 kilometres (about 2,200 miles) that make up Poland's borders with Belarus, the Czech Republic, Germany, Lithuania, Russia, Slovakia, Ukraine and the Baltic Sea.

Fishing boats will join in at sea, while kayaks and sailboats will form a chain along rivers and lakes. Prayers will also be said at the chapels of a few international airports.

- 'Spiritual barrier' -

Organisers hope one million people will show for the event. The railways are offering tickets for a symbolic 1 zloty (27 cents, 23 euro cents) to around 40 destinations on the border.

Those who are unable to attend can instead catch the event live on ultra-Catholic broadcaster Radio Maryja.

The goal is to pray for world peace, according to Father Pawel Rytel-Andrianik, spokesman for the Polish Bishops' Conference.

"The initiative obviously received the approval of Poland's bishops," he told AFP, emphasising that it would be wrong to view the event as a prayer against the arrival of Muslim refugees.

"It is not a matter of closing ourselves off to others. On the contrary, the point of bringing the rosary to the borders is to break down walls and open ourselves up to Russians, Belarussians, Slovaks, Ukrainians and Germans," he said.

But for the nationalist Catholic activist Marcin Dybowski, it is clear "that a religious war between Christianity and Islam is once again underway in Europe, just like in the past."

"Europe has been invaded by Islam, which doesn't respect our mores, our civilisation. The (terrorist) attacks leave behind hundreds of victims. Europe only makes a show of protecting borders," he said.

Dybowski, an editor of religious books, is behind the Rosary Crusade for the Motherland, a religious and political initiative bringing together ultra-Catholic nationalists.

"The reality is that there are no borders. (German Chancellor Angela) Merkel opened them up to a large extent," he told AFP.

"Poland is in danger. We need to shield our families, our homes, our country from all kinds of threats, including the de-Christianisation of our society, which the EU's liberals want to impose on us," he said.

"Austria and Hungary built barbed-wire walls against refugees. We're using prayer to create a spiritual barrier against the dangers of terrorism."