Johannesburg - Students on Saturday turned to social networking site Twitter to share injuries they sustained when the situation turned violent at a night vigil held at the University of Johannesburg. The vigil was held on Friday night.One student said her body was covered in scratches, while another posted a picture of her bruised body, claiming to have been hit by a rubber bullet. So my body is covered with scratches... And I think I might have splinters here and there too #UjNightVigil— Daughter of Azania (@IAreRori) November 14, 2015"What got me even more angry is the amount of blood [that] was flowing down my face. Think it could've filled a pint for donation," tweeted @MolefeNthabs. Many of the students accused the police of opening fire on them as they peacefully sang and danced in the street. "Students that were screaming don't shoot me were shot by the police. #UJNightVigil" the incoming SRC president at the Wits University tweeted. Just got home from UJ... Thanks @SAPoliceService pigs! #RubberBullets #UjNightVigil #OccupyUJ pic.twitter.com/HfDiaLwjTC— Ray_mundo (@Searatoa) November 13, 2015According to the University of Johannesburg, students from several institutions had come to join their students for the vigil. The vigil was reportedly being held to voice the students demands for the removal of police officers and private security campuses from the institutions.Mpho Letlape, the deputy vice-chancellor of strategic services told News24 that former general secretary of Congress of South African Trade Unions Zwelinzima Vavi and Numsa's Irvin Jim had been expected to address the crowd."At around 22:30, some people stormed the campus. The police got involved and after all that happened, there were several petrol bombs that were thrown at some of our buildings," Letlape said.One of the petrol bombs was thrown outside a building, another was hurled into the car park, while a third was thrown into an empty house owned by the school which usually housed post-grad students. All of the petrol bombs were extinguished before they could cause any major damage, said Letlape.She could not immediately confirm whether any students had been arrested during the incident.One student, however, tweeted that two students had been arrested.