The purported use of a consecrated Host at a planned satanic black mass at an Oklahoma City civic center would be a "terrible sacrilege" that requires a prayerful response, the local archbishop emphasized.

Archbishop Paul Coakley of Oklahoma City in an Aug. 4 message lamented that the city-run Civic Center Music Hall was selling tickets for the event "as if it were merely some sort of dark entertainment."

Rather, he said, the ritual was "deadly serious" and "a blasphemous and obscene inversion of the Catholic Mass."

"Using a consecrated Host obtained illicitly from a Catholic church and desecrating it in the vilest ways imaginable, the practitioners offer it in sacrifice to Satan. This terrible sacrilege is a deliberate attack on the Catholic Mass as well as the foundational beliefs of all Christians," the archbishop continued.

The occult group Dakhma of Angra Mainyu has scheduled a black mass at the Oklahoma City Civic Center Music Hall Sept. 21. A black mass is a sacrilegious ceremony that invokes Satan and mocks the Mass, involving the desecration of the Eucharist, generally by stealing a consecrated Host from a Catholic church and using it in a profane sexual ritual.

The event organizer Adam Daniels said the purported Eucharistic Host was "mailed to us by (a) friend."

"That is all I'm going to say about how it was attained," he told the Catholic news site Aleteia Aug. 6.

"As far as I know, the host mailed to me is consecrated," he said.

Daniels added that the event was intended "to educate the public about my religion."

Attendance at the event is restricted to those ages 16 and over. The sponsoring group has said the event is modified to comply with laws regarding "nudity, public urination, and other sex acts."

Daniels had attempted to hold a mock exorcism at the same music hall in 2010 as part of a different Satanist group. However, the group expelled him after learning he was a convicted sex offender.

In July, an official with the city music hall defended the decision, citing the hall's neutrality policy. She told CNA that as long as no laws were broken during the event itself, the city hall was not concerned with whether laws may be broken in obtaining a consecrated host ahead of time. She said that similar events scheduled in previous years had poor or no attendance.

Archbishop Coakley said that there are no indications the city intends to prevent the event from taking place. He encouraged Oklahomans to contact the office of Oklahoma City mayor Mick Cornett.

"I am especially concerned about the dark powers that this Satanic worship invites into our community and the spiritual danger that this poses to all who are involved in it, directly or indirectly," the archbishop said. "Since it seems this event will not be cancelled, I am calling on all Catholics of the Archdiocese of Oklahoma City to counteract this challenge to faith and decency through prayer and penance."

The archbishop has asked that every parish add the well-known prayer to St. Michael the Archangel at the end of every Mass from Aug. 6, the Feast of the Transfiguration, through Sept. 29, the Feast of the Archangels. He has also asked each parish to hold a Holy Hour with Benediction from Aug. 15, the Solemnity of the Assumption of the Blessed Virgin Mary, through Sept. 21.

The archbishop will hold a Holy Hour, an outdoor Eucharistic Procession and Benediction at Oklahoma City's St. Francis of Assisi Church at 3 p.m. Sept. 21, the same day the satanic event is scheduled to take place.

"We will pray to avert this sacrilege and publicly manifest our faith in the Lord and our loving gratitude for the gift of the Holy Eucharist, the source and summit of our lives," Archbishop Coakley said.

Tulsa's Bishop Edward Slattery and Bishop Carl A. Kemme of Wichita, Kan., have also called on the faithful to respond to the threatened desecration with their prayers.

For its part, the occult group sponsoring the black mass has organized rituals it believes will counter Catholic prayers.

A controversy over another purported black mass took place in May 2014, when the Harvard Extension School's Cultural Studies Club had planned to host a similar event on the Harvard University campus. However, that event was "postponed indefinitely" by the club amid outcry among students and member of the local community. The event reportedly took place off-campus with a small group of individuals instead.