Afghanistan, Oct. 4 -- France's nationwide high-school student protest movement has escalated into increasingly violent clashes, with Paris Police Chief Patrice Faure saying Saturday that the demonstrations were "out of control" and urging students to return to peaceful forms of protest.

Riot police clashed with students in several cities on Friday as demonstrations over overcrowded classrooms, teacher shortages, deteriorating school buildings and education funding continued to spread. Teachers' unions have also called for strike action, increasing pressure on President Emmanuel Macron's government.

Around 5,000 people, most of them teenagers, have been arrested nationwide since Monday, according to the latest figures cited by Reuters. Mo...