Venezuelan security forces faced off with stone-wielding protesters on Thursday as supporters of President Nicolás Maduro also rallied on the anniversary of last year's fatal unrest.
The flare-ups, in the volatile western city of San Cristóbal and the capital, Caracas, recalled four months of protests and violence in 2014 killing 43 people and underlined the continuing tension.
In San Cristóbal, National Guard members and police fired tear gas and buckshot against demonstrators who hurled pipes and Molotov cocktails when a march was blocked.
Five security officials and three demonstrators were hurt, some shops were vandalized, and four students were arrested in a standoff that lasted nearly two hours, witnesses and authorities said.
In Caracas, masked students blocked an avenue with burning trash and threw rocks at police who also fired buckshot in a confrontation that lasted until dusk. Witnesses said at least half a dozen youths were arrested in the melee.
Earlier in the capital, security forces cordoned off several hundred students on an unauthorized march to a church where they planned a Mass in honor of demonstrators who died. Instead, a priest went outside and briefly prayed in the open air.
In a much larger rival rally, thousands of red-clad supporters of Maduro, the successor to late socialist leader Hugo Chávez, who died of cancer in 2013, gathered in a square.
Mindful of last year's events, when thousands of opposition supporters took to the streets demanding Maduro's resignation and protesting over the OPEC nation's faltering economy, some Caracas residents stayed at home to avoid trouble.
Various businesses shut for the day or closed early.
“Venezuela today is in a far worse situation than last year. The economy is in crisis. Crime is worse. Our aim is not to topple the regime but to demand rights and changes to failed policies," said Fabio Valentini, 21, a pro-opposition student from Andres Bello Catholic University.
He was on the street protesting on Feb. 12 last year when the first people were killed in the worst unrest in a decade.
In 2014, Maduro said opposition members sought to carry out a coup, and on Thursday he said a new "coup attempt" had been foiled with the arrest of a group of Venezuelan air force officials plotting to overthrow him with the connivance of domestic political foes and the United States.
"They're in jail, the plotters," he said. He did not detail how many officials were allegedly involved but accused the U.S. Embassy of encouraging them.
Washington has repeatedly denied aiming to destabilize Maduro since he took office.