(CNN) -- Students from Washington University say they have complained to state and federal agencies that a Chicago, Illinois, nightclub barred six African-American members from their senior class trip celebration while admitting nearly 200 white classmates.
Bar personnel cited dress code violations -- specifically baggy jeans -- when barring the African-American students, according to Washington University senior class president Fernando Cutz, who was among students admitted to the bar.
A white student and a black student exchanged jeans to see what would happen, and the white student was admitted while his classmate still was kept outside, Cutz said.
Cutz said his group from the St. Louis, Missouri, school filed complaints with the Chicago Human Rights Commission, the Illinois Attorney General, the U.S. Department of Justice and other organizations after the incident on October 17. The school planned to hold a town hall meeting Monday night to discuss the incident and a possible protest, he said.
Calls by CNN to the nightclub, Original Mother's bar, were not immediately returned.
But a representative of the bar told the Chicago Tribune on Thursday that security concerns, not racism, guided the decision. One day later, a bar representative told the paper the club was taking the issue "very seriously," conducting an internal investigation and that disciplinary action would be taken if necessary.
Cutz said the celebration at Original Mother's in Chicago's Gold Coast section was to have been the culminating event of a two-day senior class trip to Chicago. The party had been arranged with the bar in advance by the student class board, which includes two of the African-American students who were later denied entry, Cutz said.
Cutz said he was already inside the bar with some 200 other students, none of whom are African-American, when the first group of African-American classmates arrived. He said he learned that the manager of the bar denied entry to the six students, and he said the manager told the students their baggy pants violated the bar's dress code.
Cutz, who is white, said he confronted the manager.
"These six [students] were better dressed than I was," Cutz told CNN.
Nevertheless, Cutz said, he told the students to "go back to the hotel and change." But the manager of the bar stepped in to say that he had made his decision and that the six men could not return to the bar even if they changed clothes, Cutz said.
The students became "more agitated" and "set up an experiment," Cutz said. Class treasurer Regis Murayi, who is black, exchanged jeans with a white student, Jordan Roberts, who -- being 3 inches shorter than Murayi -- looked "substantially baggy."
Roberts approached the same manager who had turned away the African-American students, paid the entry fee and was allowed in, Cutz said.
Washington University Chancellor Mark Wrighton sent a letter to Chicago Mayor Richard Daley to express his "most intense disappointment" about the incident. In the letter -- a copy of which was provided to CNN by Cutz -- Wrighton told the mayor that he "can only imagine the humiliation and discouragement these six young students felt ... when they were turned away from this establishment because of their race."
Students also contacted the Anti-Defamation League and the Chicago Urban League. The two organizations jointly sent a letter to the bar, writing that they "strongly suggest that Mother's re-examine its dress code, conduct immediate retraining of all employees to avoid any future racial discrimination or appearance thereof, and issue a formal letter of apology to the six students who were denied entry."