Police used tear gas, plastic bullets and a water cannon on Tuesday to break up a protest by university students against President Hugo Chavez's attempt to eliminate term limits.

Police in anti-riot gear scattered more than 2,000 students after they set out from a Caracas plaza to demonstrate against a proposed constitutional amendment that would lift term limits for all elected officials, including Chavez.

No injuries were reported.

"We didn't provoke the police. We've been victims of violence just as Chavez ordered," said student leader Juan Mejia. "We are not going to stop. We will stay in the streets."

The Chavista-dominated National Assembly approved the proposed changes to the constitution last week. The amendment goes to voters in a Feb. 15 referendum.

It is Chavez's second bid to amend the charter to run for office again. In December 2007, voters narrowly rejected a package of measures that would have scrapped presidential term limits.

Critics argue the proposed amendments would weaken democracy. Chavez's supporters say he needs more time to lead Venezuela's transition to socialism.

Chavez, who was first elected in 1998, is currently barred under the constitution from seeking re-election in 2012.

Chavez last week urged police to break up student protests if they turn violent.

Justice Minister Tarek El Aissami said the students didn't have permission for Tuesday's protest. Student leaders insisted their demonstration had been peaceful.

Chavez denounced the protests in a speech Tuesday, calling the student leaders "children of the bourgeoisie" and accusing them of trying to provoke violence.

"We aren't going to allow it," he said.