Students who took part in a protest on Monday when Chief Executive Leung Chun-ying visited City University have accused some security guards of rough treatment and are demanding an explanation from the school. About 30 students from different universities, some of them members of the Federation of Students, staged a protest on the Kowloon Tong campus to demand Leung, who was attending the opening ceremony for a new academic building, intervene in the dockers' strike and support legislation for a collective bargaining law. The strike ended on Monday, with the workers accepting a 9.8 per cent pay rise. The students said they were demonstrating peacefully at a distance from the ceremony venue when they were forcefully removed by security guards. Some guards put their arms around students' necks and twisted their arms, injuring them, they said. Johnson Yeung Ching-yin, the federation's vice-secretary general, said it was unacceptable for the university to remove protesting students simply because Leung did not want to see them. "Leung Chun-ying cannot accept opposing voices or embarrassing scenes at all," Yeung said. Vivian Yip Wing-lam, 21, president of Lingnan University Students' Union, said she and another two students were waiting for Leung outside the new building after the ceremony. Suddenly, four men in black suits pushed her and another woman to a door and told security guards to hold them until Leung left the scene, Yip said. "We are just a group of unarmed students, but the university handled us in this way. It neglected our safety," she said. Timothy Lee Ho-yin, City University student union president, said about 100 security guards were on duty that day and he wanted to know if the men in black suits were guards or police. But a City University spokeswoman said it had 77 security guards at the event, 37 of them specially brought in. It did not request police assistance, she said.