Controversy in Ireland continues after a Protestant clergyman marked the 90th anniversary of the Easter Rising of 1916 and the Western Front by celebrating mass with three Catholic priests, reported the Belfast Telegraph.

Both the Catholic Church and the Church of Ireland have promised to launch investigations after it was revealed that the minister, Rev Michael Graham, had brought 20 members of his congregation to the Augustinian Priory in Drogheda, Co Louth, where they took Communion.

The Catholic primate, Archbishop Sean Brady of Armagh, said he intended to seek further details about the event, which drew about 1,000 people.

"True ecumenism is best served by initiatives that are respectful of, and sensitive to, the traditions, ethos and discipline of all those involved," he reportedly said. "Otherwise there is a real danger of causing widespread confusion, raising false hopes and creating situations that are open to misunderstandings and manipulation."

The head of the Church of Ireland also expressed concern about the implications this incident would have on ecumenism.

“Unfortunately, such occasions - while well intentioned - can lead to misunderstandings and misinterpretations at a time when relations between our Churches have improved so much," Archbishop Robin Eames was quoted as saying.

Fr. Iggy O'Donovan, one of the Catholic priests involved, told the Irish Times he had had no intention of defying Church rules, which strictly prohibit intercommunion.