SANTIAGO, Chile (AP) — Tens of thousands of students protested in Chile on Thursday in the first march demanding education reform since President Michelle Bachelet took power on promises of deep changes.

The students marched through the streets of downtown Santiago heading to La Moneda presidential palace in a mostly peaceful protest that was marred at the end by hooded vandals who infiltrated the demonstrations to clash with police throwing rocks and petrol bombs. About 1,800 police officers guarded the march to avoid more violence. Student leaders estimated the crowd at 100,000 but police said it was closer to 40,000 people.