BOSTON — An activist group hoping to pressure the Roman Catholic Church into dropping its long-standing prohibition barring women from the priesthood says it ordained three women on Sunday.

Church officials did not recognize the ordination, and the Vatican has previously warned that women taking part in ordination ceremonies will be excommunicated.

The group known as Roman Catholic Womenpriests held the ceremony at the Church of the Covenant, a Protestant Church in Boston.

The group said the three women — Gloria Carpeneto of Baltimore, Judy Lee of Fort Myers, Fla., and Gabriella Velardi Ward of New York City — are responding to a heartfelt call to serve the church as priests.

A fourth woman, Mary Ann McCarthy Schoettly of Newton, N.J., was ordained as a deacon, the group said.

The Archdiocese of Boston issued a statement decrying the ceremony.

"Catholics who attempt to confer a sacred order on a woman, and the women who attempt to receive a sacred order, are by their own actions separating themselves from the church," the archdiocese said.

The group says the women who are ordained remain loyal members of the church and will act as priests whether they are excommunicated or not.

Sunday's ordination ceremony was performed by two women the group describes as bishops — Ida Raming of Struttgart, Germany, and Dana Reynolds from California.

The ceremony "is not in compliance with their man-made rules, but it's certainly in compliance with the Roman Catholic ordination rituals because our bishops were ordained by all-male Roman Catholic bishops who are in good standing with the church," as provided by the church's ordination rituals, said Bridget Mary Meehan, the group's spokeswoman.

The group, which was formed in 2002, has conducted similar ceremonies in the U.S. and other parts of the world.

In March, the archbishop of St. Louis excommunicated three women — two Americans and a South African who were part of the Womenpriests movement — for participating in a woman's ordination.

Pope Benedict XVI, like his predecessor, Pope John Paul II, has rebuffed calls to change traditional church teachings on the requirement that priests be male.

Catholics who are excommunicated cannot receive sacraments. The penalty can be lifted if those who have been punished are sincerely repentant.