Top local administrator Baseer Khan said on Monday police arrested the suspect in a village in Sumbal town and a fast-track inquiry is underway.
Police said the girl was hospitalized in critical condition on May 8 but her condition has stabilized.
Protests erupted Sunday and spread to new areas Monday after the suspect’s family produced a school-issued birth certificate giving his age as 13. The protesters claimed it was a fake birth certificate produced by the family to show him as a juvenile and save him from a maximum sentence of life imprisonment.
The protesters said the suspect is at least 20 and worked in a motor repair workshop. The area is 30 kilometers (20 miles) north of Srinagar, the main city in the Indian-controlled portion of Kashmir.
Police said they were questioning the school principal who issued the birth certificate.
Protesters blocked highways and fought pitched battles with government forces at several areas in the region. During the clashes, police and paramilitary soldiers fired shotgun pellets and tear gas and also fired into the air to stop stone-throwing protesters from marching on highways.
About 100 civilians and government personnel were injured in the clashes, police and medics said. One young man was said to be in critical condition.
Hundreds of students also joined protest marches demanding justice for the victim.
Khan, the administrator, appealed for calm. “Justice will be done and the culprit will be given fair punishment as per the law,” he said.
India has been shaken by a series of sexual assaults in recent years, including the gang rape and murder of a student on a moving New Delhi bus in 2012. That attack galvanized a country where widespread violence against women had long been quietly accepted.
While the government has passed a series of laws increasing punishment for rape, it’s rare for more than a few weeks to pass without another brutal sexual assault being reported.