Chavez supporters wore red, the colour of his party, during rallies
Tens of thousands of people have marched through the Venezuelan capital, Caracas, in rival demonstrations for and against President Hugo Chavez.
Opponents held a rally against what they called the president's growing authoritarianism.
They were concerned about an education law they fear could lead to socialist indoctrination in schools.
Meanwhile, one government minister told Chavez supporters that 29 more radio stations would be closed, reports said.
The radio closures are part of a continuing campaign against what the government considers to be right-wing media, with 34 stations already closed down.
The anti-Chavez protesters were angry about a new education law that boosts the government's control over schools and universities.
The law requires schools to base their teaching on "the Bolivarian Doctrine" - a reference to the ideals of 19th Century independence hero Simon Bolivar, such as Latin American unity and national self-determination.
Anti-Chavez protesters fear his new education law
A previous attempt at education reform was one of the factors that led to mass protests in 2002, eventually culminating in a failed coup attempt against Mr Chavez.
"It's very concerning because education is Venezuela's future," engineering student Carlos Delgado told the Associated Press news agency.
Opponents were also angry at the government for shutting dozens of radio stations last month.
More were expected to be shut, Infrastructure Minister Diosdado Cabello announced on Saturday.
"Another 29 will be gone soon," he told a pro-Chavez rally, Reuters reported.
At other rallies in Caracas and elsewhere, thousands of Chavez supporters dressed in red and danced to salsa to counteract the opposition protests.
"We are here today to support our president and reject the opposition march," said parliament worker Nelson Guanchez, 27, told Reuters in Caracas.
Mr Chavez - who is in Iran as part of an overseas tour aimed at building a new alliance to counter the global dominance of the US - spoke by phone to the rally.
He told supporters he was proud of them, and shouted a popular "Chavista" slogan, Reuters said: "Homeland, socialism, or death".
The rallies came a day after protests across Latin American about Mr Chavez's policies.
Friday's demonstrations were organised by Colombian activists after Mr Chavez criticised Colombia for allowing US forces access to seven military bases.
The Venezuelan leader has already frozen diplomatic relations with Colombia and blocked bilateral trade.
An estimated 5,000 people took part in protests in the Colombian capital Bogota, and thousands more in the capitals of Venezuela and Honduras.
Smaller demonstrations were held in other Latin American capitals, as well as in New York and Madrid.