Rev. Michael Pfleger has been asked to step aside because of allegations of sexual abuse that occurred decades ago, the Archdiocese of Chicago announced Tuesday.

The archdiocese said its Office for Child Abuse Investigations and Review received an allegation that Pfleger sexually abused a minor more than 40 years ago. Cardinal Blase Cupich sent a letter to members of the Faith Community of Saint Sabina, where Pfleger is the pastor, that said the allegation hasn’t been proven as true or false and guilt or innocence should not be assumed.

“In the days and weeks ahead, members of the archdiocese’s Office for the Protection of Children and Youth will be available to answer any questions you may have and provide you with support during this challenging time,” Cupich said in the letter.

Telephone calls to the church for comment were not answered. However, St. Sabina leaders released a statement saying they believe the accusations are unfounded and that Pfleger will be exonerated.

“We will stand with him during this process as he had stood with victims of injustice,” the St. Sabina cabinet said in the statement.

Parishioner Ernest Sanders said he’s known Pfleger for three decades.

“I really was taken back that folks would actually believe something of this nature, knowing his history, knowing his passion for life and not death,” said Sanders. “I just really honor him, his commitment to the Gospel, his commitment to the South Side of Chicago, to Black and brown people, to making sure that the marginalized have every opportunity available to them.”

According to the archdiocese, Pfleger has agreed to live away from the parish while he is being investigated. Father Thulani Magwaza will lead St. Sabina Church while authorities investigate the allegations against Pfleger, Cupich said.

The archdiocese said the allegation of sex abuse by Pfleger was reported to the Illinois Department of Children and Family Services and the Cook County State’s Attorney’s Office.

Pfleger has served as pastor at St. Sabina Church since 1981. As an anti-gun violence advocate he has become one of Chicago’s most outspoken activists, leading marches to bring attention to the issue. His most recent march was on New Year’s Eve, when he led dozens along Michigan Ave. to exhort city leaders to pay attention to the “virus of violence.”

Pfleger has also been active in the Black Lives Matter movement and participated in Civil Rights marches around the nation.

WBEZ’s Linda Lutton contributed to this report.