Protesters killed 2 police officers with a bus in one of Venezuela's most volatile cities
Protests broke out near the Agroindustrial University Institute (IUT) in southern San Cristobal, according to Venezuela-based blog Caracas Chronicles.
In response, police barricaded streets near the IUT in order to contain the demonstrations.
Protesters hijacked a passenger bus from a nearby terminal and attempted to drive it through a police cordon to the university, where about 70 demonstrators were rallying against a nationally decreed bus-fare hike.
"We regret the loss of life of police officers who were carrying out their duties," state Governor Jose Vielma tweeted. "We reject any act that threatens stability and the lives of citizens. Violence brings bad consequences," he wrote.
One of those killed was a 25-year-old member the National Police, and the other was a 20-year-old officer of the Táchira state police.
The opposition alliance hopes protests, a recall referendum, or a constitutional amendment will force Maduro out of office this year. Maduro has rejected their efforts, saying his government is the one to steer the country out of its current morass.
"We are here to work undisturbed in the great objectives of the economic recovery," Maduro said during a meeting with businessmen and senior government officials in early March. "And from there, they will not get rid of me, nor should they get rid of anyone."
While the opposition has made protests a central pillar in its anti-Maduro strategy, recent demonstrations have failed to draw the people and fervor they have in the past, as many Venezuelans appear drained by years of crisis and scarcity.
Two years ago, San Cristobal was the epicenter of nationwide anti-government protests that dragged on for weeks and left more than 40 people - security forces and anti- and pro-government demonstrators - dead but failed to push President Nicolas Maduro from office.
Despite the protests, the enduring impasse, and dissatisfaction with the current political environment, some Venezuelans still want country's rival factions to negotiate.
"I don't support either side as they're both the same," Miguel Contrera, a 57-year-old shoe-shiner who avidly supported Chavez until his death in 2013, told Reuters in mid-March. "They need to come to an agreement to improve things."
Reuters contributed to this story.