Ozier Muhammad/The New York Times

A daylong rally by City University of New York students against a planned tuition increase turned turbulent Monday evening when marchers ignored police requests to clear the lobby of a building at Baruch College where the university’s trustees were meeting and 15 people were arrested.

The students were pushed to the ground and taken away in handcuffs from the lobby of the college, in Manhattan, while protesting against the proposal for tuition increases, which CUNY’s Board of Trustees is scheduled to vote on next Monday.

Carlos Pazmino, 21, a City College student who helped organize the protest, said that after students began opening doors to the auditorium where the CUNY trustees were to hold a public hearing at 5 p.m., CUNY police officers surrounded the entrances and pushed back, using their batons, and that when students formed a line to push past, the officers began hitting the students with the batons.

“I saw two people knocked down by cops,” Mr. Pazmino said. “They were arrested and one guy’s head was bleeding.”

Video posted to Facebook by the Baruch College newspaper, The Ticker, (see below) and photos showed a chaotic scene and its aftermath.

During the fighting, students on higher floors dropped books down on the police, and captured the scuffle on video. A crowd of 200 to 300 protesters outside beat on the lobby’s windows, also shouting, “Shame.”

The police did not immediately say how many people were arrested.

The meeting went on as scheduled on the 14th floor of the building, where people who had made it into the hearing started receiving text messages about the events in the lobby.

The protest had begun with a handful of organizers from Students United for a Free CUNY, who marched through the school cafeteria at City College at lunchtime. The group is demanding the repeal of the tuition increase approved last summer by the city and the state: $300 a year for each of the next five years.

Later in the afternoon, the protest moved to Madison Square Park, where CUNY students from other colleges had agreed to meet. The growing crowd then marched on to Baruch College, at Lexington Avenue and 24th Street.

Videos posted on YouTube by user Michael Alexander Gould-Wartofsky showed a line of officers pushing into a crowd of students.

At Baruch, the campus police restricted access to the hearing to those who had registered, and set up barricades around the building, the William and Anita Newman Vertical Campus Conference Center.

With the room at capacity and hundreds of people surrounding the building, the police told those in the lobby that they would be arrested for trespassing. At that point, the students in the lobby sat down, and some were pushed to a wall by the campus police. Nearly a dozen people were arrested as officers cleared the room as several hundred people protested outside.

“We have made it clear to the university that violent response to students who are protesting nonviolently is not acceptable,” said Barbara Bowen, the president of the CUNY Professional Staff Congress, who was at the meeting while the students were being arrested.

At the afternoon protest at Madison Square Park, protesters chanted, “Banks got bailed out, students got sold out.”

A small group of New York University and New School students joined the rally to support CUNY students, apparently part of an unrelated campaign by Occupy Wall Street organizers called Occupy Student Debt. Andrew Ross, an N.Y.U. professor affiliated with that group, said it was aiming to get one million students to pledge that they would not pay back their loans.

But Denise Romero, 19, a junior at Baruch and one of the organizers of Monday’s protest, insisted that the CUNY protest was independent of Occupy Wall Street. “We support them and they support us, but we are not affiliated,” she said.

She added that CUNY students were protesting not only tuition increases but also the university’s push for a public-private partnership. CUNY received $1.4 billion in private philanthropy this year, according to a university spokesman.

“We want more student representation,” said Ms. Romero, who had registered to speak at the hearing Monday. “We want to change the way they decide things.”