BERLIN (AP) — Defying a papal admonition against receiving communion in churches that are not Roman Catholic, a lay organization that aims to reform the Catholic Church said it plans to share communion with Lutherans on the sidelines of a major German ecumenical conference.

"It is neither unique nor new for Christians to issue invitations to each other," said Eva Maria Kiklas, of the We Are Church movement, which believes celibacy should be optional for priests and wants a greater role for women in the church.

Her group, along with an ecumenical organization, the Church from Beneath Initiative, plan to hold a Roman Catholic Eucharist at a Lutheran church in the capital, followed by an open communion. They will later hold a joint Lutheran communion.

Disturbed by what he sees as abuses of sacred practices, Pope John Paul II in April issued a stern reminder that services in Protestant churches cannot substitute for Sunday Mass.

With more than 200,000 participants, the ecumenical conference which runs through the weekend, is the first of its scale to bring together members of Germany's predominant Catholic and Lutheran churches. The shared communion is not condoned by organizers of the event.

Catholic Cardinal Karl Lehmann, who heads the German Bishops Conference, said he regretted that shared communions were planned.