The students, who attend the upstate New York campus, said they were harassed and assaulted while riding the bus early Saturday morning, according to a letter to the campus from the university's president, Robert J. Jones.
According to the three women, who have not been identified by authorities or the university, a group of 10 to 12 white men and women used racial slurs and physically assaulted them, Jones said.
One of the alleged victims spoke at the rally, according to CNN affiliate WTEN
. "We are shocked, upset, but we will remain unbroken. We are proud of who we are," she told the gathered crowd through tears.
The incident was caught on cell phone video and video from the Capital District Transportation Authority bus, university police Chief J. Frank Wiley said in a statement.
A review of the video, which has not been made public, shows the incident started with verbal exchanges, which became physical after the bus was on the university campus, according to police.
Campus police said Monday that 34 people of interest were identified by video. Police identified 29 and interviewed 16.
The allegations of the use of racial slurs are being taken "very seriously," said Steven Smith, spokesman for the Albany police department, which is coordinating efforts with university police in the ongoing investigation.
After the incident, the hashtag #DefendBlackGirlsUAlbany appeared on social media in support of the three women.
Police said they are working to learn the identity of the individuals involved, as well as any potential witnesses.
"I am deeply concerned, saddened and angry about this incident," said Jones. "There is no place in the UAlbany community for violence, no place for racial intolerance and no place for gender violence."
He added that campus police, "our student affairs personnel and our Office of Diversity and Inclusion staff are working together to support our young women."
The rally Monday evening was to demonstrate the university's commitment to "promoting a campus community of acceptance and inclusion," according to a university statement, and it was to be followed by an annual Martin Luther King Jr. celebration.
The university has approximately 17,000 students, with African-Americans making up 15% of the student body.
Campus police said that while there's no evidence of a continued threat, the department has assigned additional personnel to monitor campus safety.