Water cannons and plastic bullets were used by police against Venezuelan students protesting increased government control over universities.
At least four people were injured, including a news photographer who was treated for a cut to the head after being hit with an object.
Dozens of police and National Guard troops in anti-riot gear blocked protesters including students and professors outside the Central University of Venezuela in Caracas, firing plastic bullets into the air and also at demonstrators.
The law governing universities was approved by the National Assembly before dawn Thursday, and students denounced it as an attempt by President Hugo Chavez to clamp down on autonomous state universities that have been a bastion of opposition to his government.
"They won't take away our right to protest," the protesters chanted. "Long live the university! ... Out with the military boot!"
The law gives Chavez's higher education minister broad powers to decide on academic programs and university operations, and says universities should promote education that reinforces the government's aim of building a "socialist homeland."
Anti-Chavez protesters say the law gives too much power to the national government and also seeks to impose socialist ideology.
The students had planned to march to the National Assembly but were turned back. Later, hundreds of students managed to continue the march through Caracas on another route, evading authorities who were firing plastic bullets and a water cannon, and shouting: "People, listen! This is a dictatorship!"
The protest ended peacefully once they circled back to Plaza Venezuela near the university.
"We came out to protest against this unconstitutional law, and as is customary under totalitarian governments, they didn't let us leave," said Diego Scharifker, student federation president at the university.
Scharifker said the law "imposes socialism as the sole ideology, does away with university autonomy because it concentrates all powers in the higher education minister."
The law is the latest in a series of controversial measures enacted in the final days of a solidly pro-Chavez National Assembly before a new legislature takes office Jan. 5 with a bigger opposition contingent capable of hindering some types of laws.
University rector Cecilia Garcia Arocha said two of those hurt during the protest included Chavez opponent Antonio Rivero, a retired general who was injured in the back with plastic bullets; and a professor from another university who was hit in the head with an object. An AP journalist also captured footage of a student injured in the back with plastic bullets.
Two students were briefly detained, then released.
"We don't agree with the way they passed this law without consultation," said Ivan Gomez, a 17-year-old political science student who said he was grabbed and taken away by two National Guardsmen, then later released. His clothes were soaked from the water cannon.
More protests are planned in the coming days, said Garcia Arocha, who called the law unconstitutional and said the university plans to maintain its autonomy.
University autonomy has been an emotional issue in many nations, especially in Latin America, where students and professors long struggled to maintain some independence from dictatorial conservative regimes -- seeing the school as an island where critical thought is allowed. The concept usually involves allowing universities to choose their own administrators and forbidding outside police or troops from entering campuses.
Chavez's socialist government has defended the law saying it seeks to make the universities more inclusive and democratic.
Earlier this week, pro-Chavez lawmakers also pushed through a law barring foreign funding for political parties or nongovernment organizations that promote "political rights," adding to a series of measures that critics say aim to stifle dissent.
The U.S. State Department said in a statement Thursday that it is "deeply troubled" by the law. "Under the Inter-American Democratic Charter and other international instruments, the Venezuelan government has made a commitment to act in accordance with democratic values that include freedom of expression, pluralism and openness," it said.
Other newly approved laws boost the Venezuelan government's powers to intervene in the banking sector, bar some types of messages on the Internet, make it easier to revoke the licenses of TV or radio stations and give the president power to enact laws by decree for 18 months.
Newly elected opposition lawmakers said in a joint statement Wednesday that the laws are dismantling democracy and represent a "coup d'etat by the state." They called the laws unconstitutional.
Chavez defends the decree powers as necessary to speed relief after recent floods and mudslides as well as to accelerate his government's socialist-oriented policies.
The decree powers will allow Chavez to pass laws without consulting lawmakers in a range of areas after the new National Assembly takes office next month.
Another law passed this week allows for the suspension of lawmakers who abandon their political party while in office -- a move meant to block the kind of defections that saw a dozen legislators break with Chavez during the current session.
Lawmakers have also rewritten parliamentary rules shortening the times allowed for debates and giving more power to the National Assembly president and Chavez's party, which will have a majority with 98 of the 165 seats.
The Associated Press contributed to this report.