Security forces used tear gas, pepper spray and rubber bullets to scatter students who came out on the streets of Caracas to protest socialist President Nicolas Maduro.
The clashes began after authorities closed subway stations, set up checkpoints and cordoned off a square where opponents had planned their latest protest.
In cat-and-mouse skirmishes on backstreets and highways around the capital, youths built barricades, burnt trash and hurled rocks and bottles at soldiers and police.
Various opposition leaders organised roadblocks.
Police used pepper spray on National Assembly head Julio Borges, two-time presidential candidate Henrique Capriles and rights activist Lilian Tintori, as they led protesters onto highways, witnesses said.
Opposition activists said armed pro-government gangs joined the fray and opened fire.
"About 50-100 guys arrived on bike and started to shoot in the air," protester Bernardo Sanchez told local media.
He said a bullet had lodged in his thigh.
The protestors vented their anger against a government they blame for a deep recession that has led to shortages of food and basic necessities.
Protests were also staged in other cities and more are planned across the country for Thursday.
The government accuses opposition parties of abetting a US-led plot to topple Maduro, who has ruled Venezuela since the 2013 death of Hugo Chavez.
TRT World spoke to journalist Juan Carlos Lamas in Caracas.
Tensions spike after court ruling
Tensions have soared in the oil-producing country's long-running political standoff after the pro-Maduro Supreme Court last week annulled the opposition-led congress' functions.
Although the court retracted that ruling over the weekend, the National Assembly remains powerless due to previous court judgement.
Foreign pressure on Maduro has risen as opposition protests resumed late last week.
"Here the world can see the dictatorial path Mr Maduro has chosen," Capriles said.
Venezuela's opposition won a National Assembly majority in late 2015 but the Supreme Court has overturned almost all its measures.
Due to the chaos in Caracas, the legislature postponed until Wednesday a session to censure the "rupture" of Venezuela's constitution.
Legislators also plan this week to start proceedings to remove Supreme Court judges but that would only be a symbolic rebuke since congress has no power to act.