Venezuelan police have fired teargas to stop thousands of protesters against a new education law from breaking past a security cordon in the capital Caracas.
Protesters accuse the government of President Hugo Chavez of indoctrinating children into backing socialist values.
Health officials said dozens of people were treated for minor injuries.
Rallies for and against the law, which passed last week, have been held for over a week. Last Friday’s protests also met a tough response from police.
Elsewhere in the capital on Sunday, thousands of Chavez supporters held a counter-rally.
They say the new law will give everyone equal access to education, regardless of their economic position.
The government says changes to the law – which among other things, broadens state control over schools and makes the education system secular – were long overdue.
But the Catholic Church and university authorities in Venezuela have opposed the law.