People take to streets in northern Sri Lanka demanding justice for a gang-raped teenage girl, in the biggest demonstration recorded in the region.

The Wednesday protest in Jaffna, the capital of Northern Province, turned violent with cops firing tear gas at the demonstrators seeking justice for murder and gang rape of the 17-year-old schoolgirl last week.

Arrests were also made at the protest, which brought the city to a standstill, leading to closure of banks and schools.

Last Wednesday, the girl went to school but never returned. A day later, her body was found in the nearby island of Pungudutivu, with reports saying that her hands and legs had been tied and a rag stuffed into her mouth.

The demonstrators demanded the government hand over the nine men detained following the incident.

"The brutal way this schoolgirl has been attacked is shocking and that’s why we are so angry," a lecturer at the University of Jaffna told al-Jazeera.

The protest, joined by schoolchildren and groups of young people, began peacefully but turned violent later, with police trying to disperse the crowds and the demonstrators throwing stones at the courthouse.

"There was an outbreak of violence within a very short period - we are investigating the cause of this," said the deputy inspector-general of police in Jaffna, GK Perera.

Damaging public property and participation in unlawful protests are among the charges the detainees, more than 100 people, face.

The demo was reportedly the largest of its kind in the area.

NT/AS/MHB