Student protests turn violent in Chile capital Santiago
Students and police have clashed in the Chilean capital, Santiago, during the latest protest over education reform.
Police used tear gas and water cannon against masked protesters who set up barricades and threw petrol bombs.
With more demonstrations planned for Wednesday, the government has said it will invoke an emergency security law to help quell the violence.
The protest movement - which started in May - is the biggest in Chile since the return to democracy in 1990.
The students, backed by teachers and trade unions, called the latest two-day national strike after talks with the government broke down earlier this month.
'Too much hate'
The violence began early on Tuesday as protesters set up burning barricades on several main avenues across the capital, blocking rush hour traffic.
Masked assailants set fire to a city bus, and police raided university buildings in pursuit of suspects.
More than 60 people were arrested, police said.
Interior minister Rodrigo Hintzpeter said those responsible for the bus attack would be prosecuted under the rarely-used Law of State Security, which allows tougher sentences for violent offenders.
"We have seen too much violence, too much senseless destruction, too much hate," he said.
Student leaders have condemned the violence and say it is not related to their movement for educational reform.
Representatives of the movement went to the heavily guarded presidential palace to present an unofficial plebiscite on their demand for educational reform.
More than 1.5 million people took part in the plebiscite, with 88.7% voting in favour of free, public, high quality education, the organisers said.
Student leaders are demanding wholesale reform of Chile's education system, which they say is unequal and under-funded.
They want the central government to take full control of education and increase spending on public schools and universities.
President Sebastian Pinera has responded by promising limited reforms and around $4bn (£2.6bn) in extra funding.
On Tuesday he approved a law increasing subsidies for children from poor backgrounds attending private schools.
But he has categorically rejected calls for full state control and free education.