DENVER  —  A national group that monitors the separation of church and state says it may sue the Air Force Academy (search), claiming the school allows evangelical Christians to harass cadets who do not share their faith.

"This is the most significant, systemwide example of religious discrimination I have seen in a military setting. Every cadet should be treated as a first-class citizen but instead those who are not evangelical Christians have a lower status," said Rev. Barry Lynn, executive director of Americans United for Separation of Church and State (search).

Lynn's group said it conducted a two-month investigation that included contacting about 15 cadets and staff, and has sent a report to Defense Secretary Donald H. Rumsfeld (search).

The investigation found that former and current cadets said that their fellow students, faculty, staff and members of the chaplains' office frequently pressured them to attend chapel and receive religious instruction. In one case, a professor required a prayer before a test, and faculty members have promoted their religion in class, the group said.

An academy spokesman declined comment. Air Force spokeswoman Lt. Col. Amy Rogerson said Friday the report had not yet been received and she could not comment on its contents.

"The Air Force's position is that one's religious beliefs, or the absence of beliefs in an established religion, should never be grounds for unlawful discrimination," Rogerson said. "The Air Force senior leadership has total confidence in the academy."

The academy has launched mandatory religious tolerance classes after complaints from Jews and other cadets that they are the target of religious harassment and insults by Christians. Some have also questioned the activities of senior leadership at the prestigious school near Colorado Springs.

Lynn said his group would work with the Air Force and Congress, but warned a religious discrimination lawsuit is possible if there is no progress in 30 days.