Gunmen in Venezuela have opened fire on students returning from a peaceful march in Caracas against President Hugo Chavez's planned consitutional reforms.
Some of the gunmen opened fire on students from motorcycles
At least eight people were hurt during the clashes on a university campus, including at least one by gunfire.
The students were protesting against plans to remove presidential term limits, the subject of a referendum.
Thousands had marched to Venezuela's Supreme Court and filed a demand for the December vote to be suspended.
Last week, troops used tear gas and water cannon to disperse thousands of students protesting in Caracas against the proposed amendments.
It is unclear how Wednesday's violence erupted.
A number of gunmen arrived at the Central University of Venezuela campus on motorcycles, law faculty dean Jorge Pabon told AFP news agency.
They set a bus alight, and later fired at students from inside one of the university buildings.
State TV showed footage of angry students setting fire to benches and throwing rocks at the university building where the gunmen were hiding.
Photographers for the Associated Press news agency saw at least four masked gunmen firing handguns at the crowd, as terrified students fled.
Globovision television, which is openly critical of the government, showed images of hooded men throwing objects into university classes and other people, apparently students, running away.
Civil defence chief Antonio Rivero said at least eight people were hurt, one of them by gunfire.
The government described the protest, one of several recent student-led demonstrations against the constitutional reforms, as an opposition effort to destabilise the country ahead of the referendum on 2 December.
The amendments up for approval include giving the president control over the central bank, and the creation of new provinces governed by centrally appointed officials.
President Chavez is also proposing to bypass legal controls on the executive during a state of emergency, bring in a maximum six-hour working day, and cut the voting age from 18 to 16.
Supporters say the changes will deepen Venezuela's democracy but critics accuse Mr Chavez of a power grab.