MILWAUKEE -- A 64-year-old woman faces excommunication for seeking the priesthood in an unsanctioned ordination ceremony in Pittsburgh last month, the Milwaukee Archbishop said.

The Roman Catholic Church prohibits women from becoming priests, and Milwaukee Archbishop Timothy M. Dolan said in a statement that it was his duty to notify the Vatican of her action.

Kathy Sullivan Vandenberg and 11 other women took part in an ordination ceremony July 31 conducted by the group Roman Catholic Womenpriests -- eight to become priests and four to become deacons.

Similar ceremonies conducted by Roman Catholic Womenpriests have been held before in other countries, and most of the participants have been excommunicated. The Pittsburgh ceremony was the first in the United States.

Dolan said her excommunication could come soon but Vandenberg said it was only a punishment.

"That doesn't mean I'm excluded from the church. Only I can exclude myself," she said.

The archbishop said in his letter handed out at Vandenberg's home parish that he was "disappointed because Ms. Vandenberg and I had begun a fruitful dialogue on the matter last fall."

"At that time ... I had advised her that any attempted ordination would affect her relationship with the church," he wrote.

"I believed her sincerity when she assured me that she was unaware of such a consequence, and did not want that to happen," he added.

Vandenberg said Monday that she was startled by the letter and surprised that Dolan had "spent so much time and energy" on it when "other important things" might demand his attention.