Despite a strong protest, a satanic black mass at the Civic Center in Oklahoma City is expected to go ahead as planned on September 21.

Devil-worshipping organisation Dakhma of Angra Mainyu is hosting the event, which mocks the traditional Catholic mass. The ritual often involves desecration of the Eucharist, and inviting the devil in instead of casting him out.

The American Society for the Defense of Tradition, Family and Property (TFP) Student Action Director, John Ritchie, said the ceremony is sacrilegious.

"The black mass is the most obscene attack against the Catholic mass that can be imagined," he told the Christian Post. "It harms the moral fabric of our nation and that's the primary reason I oppose it. The highest reason is that it offends God."

Ritchie's organisation began the petition to block the satanic mass from occurring. The effort has received over 75,000 signatures.

"For someone to deliberately attack the supreme good, [God], intentionally, to cause harm [and be] deliberately filled with hatred is something that not only hurts Catholics and Christians, in general, but everybody of good will," Ritchie stated.

He also questioned the city's decision to approve the mass.

"Why is the Civic Center facilitating and advertising this sacrilege, using its tax-funded facility as a platform to attack God and demean all God-loving Americans?" he asked in July.

"For someone to deliberately attack the supreme good, [God], intentionally, to cause harm [and be] deliberately filled with hatred is something that not only hurts Catholics and Christians, in general, but everybody of good will," Ritchie insisted.

A consecrated host was reportedly stolen from a Catholic church to be used in the black mass, but has been returned.

Oklahoma City Archbishop Paul Coakley called for prayer and penance to counteract the satanic ceremony.

In a statement, he invited all "people of good will" to join him in prayer for a "Holy Hour" and outdoor Eucharistic Procession and Benediction at St. Francis of Assisi Church in Oklahoma City at 3:00pm on September 21.

"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," he said.