Two police officers have died in El Salvador after clashing with students at a protest over bus ticket prices.
Violence broke out when police fired tear gas at protesters
At least 10 other officers were wounded in the violence, which broke out when police fired tear gas to disperse protesters in the capital San Salvador.
The demonstrators responded by shooting in the air and vandalising patrol cars and officers made 20 arrests.
Police had no information on student casualties, but a university employee was reportedly shot in the chest.
Faculty member Herbert Rivas was shot during a meeting in the rectory, said University of El Salvador official Eduardo Espinoza.
Mr Espinoza accused officers of firing on the university buildings from a helicopter, but police have denied this.
TV images showed officers with extensive wounds
The students had gathered at the university to protest against a hike in electricity rates and public transport fees.
The government recently took an unpopular decision to increase the cost of a bus ticket in response to rising global energy prices.
Television images from the clashes showed police officers with wounds on their heads, abdomens and legs.
President Tony Saca condemned the killing of the two officers and blamed the violence on the opposition Farabundo Marti National Liberation Front party (FMLN).
The FMLN fought a 12-year civil war against the government before becoming a political party in 1992.
"I have always said the FMLN has people disguised as protesters, who really are killers and dangerous people," Mr Saca said.