Two 16-year-old boys have been arrested for allegedly murdering two girls in Soweto, southwest of Johannesburg, South African police said on Thursday. The arrests were made on Thursday after an intense investigation in the past 24 hours, police spokesperson Neville Malilla said. The two boys will appear in the Johannesburg Magistrate's Court on Friday. The motive for the killing remains unknown. The two girls, aged 15 and 16, were found murdered in Soweto Wednesday morning in the latest case of rising violence against minors. Dressed in school uniforms, the girls were attacked while on their way to school. They had cuts on their hands and necks, according to police. Police recovered black candles, razor blades and their school bags next to their bodies. Johannesburg has witnessed a surge in violence against minors. Since last year, almost 10 girls have been murdered. In an incident that shocked the nation in October, two girls, aged two and three, were murdered in Diepsloot north of Johannesburg, and their bodies were dumped in a public toilet. The two girls were found half naked and mutilated earlier this month. Police suspected that they were raped before being murdered. South Africa has one of the highest crime rates in the world, with children and women often falling victim to criminals. Figures from the Children's Institute at the University of Cape Town also showed that an average of three children are murdered daily in South Africa.