GREAT FALLS, Mont. (AP) — A former Indian Health Service pediatrician accused of sexually abusing young boys on Montana's Blackfeet Indian Reservation two decades ago had his trial delayed Monday because of "an unforeseen issue," court officials said.

Stanley Patrick Weber, 69, is charged with aggravated sexual abuse and attempted sexual abuse of two boys under 14 when he worked on the reservation between 1992 and 1995.

He also is accused of abusing four other boys after he was assigned to South Dakota's Pine Ridge Reservation in 1995, where he worked until he left the Indian Health Service in 2016. Those charges are still pending, but federal prosecutors are expected to call them to testify in the Montana trial.

Weber has pleaded not guilty to the charges. His attorneys did not respond to an email request for comment.

The trial in Great Falls was supposed to get underway Monday with jury selection, but it was rescheduled to Sept. 4 over what U.S. District Court officials described in the docket without elaboration as "an unforeseen issue (that) arose over the weekend."

Prosecutors accuse Weber of abusing one boy on multiple occasions at his office during exams and abusing or trying to abuse the other boy at Weber's home, where the pediatrician would frequently host juvenile boys.

Prosecutors said Weber groomed potential victims by plying them with money, candy, alcohol, video games and trips, earning their trust and teaching them about sexual activity before isolating and abusing them.