(CNN) -- The University of North Carolina failed some of its students "for years" by allowing them to take classes that did not match its own academic standards, Chancellor Carol Folt has admitted.
The concession -- the strongest since UNC-Chapel Hill was caught up in a fake-class scandal two years ago -- comes just weeks after a CNN investigation found continuing problems at UNC and other public universities where some student-athletes could read only at an elementary school level.
Two years ago, it was exposed that UNC students, many of them athletes, were given grades for classes they did not attend and for which they did nothing beyond turning in a single paper. One professor has been indicted on fraud charges for being paid for a class he didn't teach.
The university has always maintained it was an isolated case, but Folt is now acknowledging a broader problem.
"We also accept the fact that there was a failure in academic oversight for years that permitted this to continue," Folt told UNC trustees last week.
"This, too, was wrong. And it has undermined our integrity and our reputation."
CNN has asked UNC Chapel Hill for the number of students who were specially admitted because they did not meet the usual academic standards and who majored in or took the classes now acknowledged as fake.
CNN investigated the issue of poor academics among student football and basketball players after a researcher at UNC revealed that some could not read well enough to follow news coverage about themselves or even read the word "Wisconsin."
The researcher, Mary Willingham, said student-athletes were among those who took the fake classes, though she said the classes were just a symptom of the problem of enrolling athletes in the money-making sports of football and basketball who could not succeed academically by themselves.
While questioning Willingham's credibility and CNN's reporting, UNC has launched its own investigation into the claims that too many of its student-athletes read poorly.
And the university's executive vice chancellor and provost, James Dean, told Bloomberg Businessweek that he had commissioned an internal study into African and African-American studies at the university. That's where the fake classes originated.
UNC spokeswoman Karen Moon said Tuesday that as part of the study, Dean is "interested in better understanding the formation of the department as part of our ongoing efforts to assess the overall academic environment at the University."
UNC had previously done an internal investigation, and told CNN last fall that it implemented changes based on what its internal report found. Some 120 changes were made and UNC told CNN they felt that was sufficient to ensure it knew what happened and to make sure it would not happen again.
Dean told Bloomberg Businessweek, whose parent company's chairman is a UNC trustee, that he would investigate whether student-athletes were "clustering" in departments or classes that were supposed to have easy grades and to see whether there were any other forces or personalities behind the scandal.
UNC told CNN last year it has a program that alerts it if too many athletes are enrolled in a single class, but it's not yet clear whether this is different.
Neither Dean nor Folt were in their positions when the fake classes were run. The NCAA, which oversees college sport, did investigate, but found none of its rules were broken.
The NCAA told CNN on Monday it won't comment on whether the university will take a second look.