The chancellor of Washington University has told Chicago Mayor Richard Daley that he is "deeply disappointed" about a recent incident in which six black students were denied access to a Chicago nightclub.

In a letter sent last week, Chancellor Mark Wrighton asked Daley to investigate the matter fully and to "take the steps necessary to ensure that similar incidents do not occur to future visitors to the City of Chicago."

The six Washington U. students were not admitted to Mother's Nightclub Original in Chicago on Oct. 17 during a class trip sponsored by the school's Senior Class Council. More than 200 students attended the event. The students were told that they did not comply with the club's "baggy jeans" policy, but the students believe the real reason they were turned away was racial discrimination.

The students said a bar manager refused to consider admitting them even after they offered to change into different clothes. And they said a white student who later put on the jeans of one of the barred students was admitted inside that same night.

Lance Lewis, a Daley spokesman, said Monday that the city's Commission on Human Relations is investigating the incident. "Everyone is welcome in Chicago," Lewis said.

The students also have filed complaints with the Illinois attorney general's office and the U.S. Justice Department.

An employee of the management group that runs Mother's Nightclub Original said on Monday that the club is in the midst of an internal investigation and would release a statement on the matter "shortly."

Representatives of the club told the Chicago Tribune last week that the students were denied entrance because of security concerns and noted that gang violence was common in the area. They said it was not an issue of racism and noted that other black patrons were allowed in.

In his letter to Daley, Wrighton wrote that Washington U. students are bright, optimistic and "eager to tackle our world's most pressing challenges."

"I can only imagine the humiliation and discouragement these six young students felt last weekend when they were turned away from this establishment because of their race," Wrighton wrote. "I am hopeful that this incident has not in any way damaged their perspective and their sense of self-esteem, but I doubt that is the case."

He continued: "Chicago is a great city and Chicagoans can take pride that one of their residents was the first African American to be elected President of the United States, but the experience of our students represents a setback for the City and reveals that we still have much work to do to achieve true racial equality in this country."

Regis Murayi, one of the students who was barred, said he's grateful the university has thrown its support behind the students. He said he's still upset about what happened and thinks about it every morning. But he said he's also trying to move on from it.

Washington U. students held a forum Monday night to discuss the incident.