Saturday's protests continued a week of unrest sparked by last week's Supreme Court decision in which it assumed the role of the opposition-led congress.
Maduro said in a televised address on Thursday that authorities had detained 30 people involved in the demonstration as the country's fragmented opposition gained new impetus against a government it blames for the country's social and economic meltdown.
Police in Caracas fired tear gas and rubber bullets at some of the protesters amid a weeklong protest movement that shows little sign of losing steam.
AFP reporters also witnessed a National Guard soldier lying unconscious after having been struck by a large rock. Around 4,000 people attended the demonstration. "But today they can see that what is happening here is a humanitarian crisis", he said.
At the height of Saturday's crackdown by police, Mr Smolansky took to Twitter to accuse Mr Maduro of "beginning to use chemical weapons as is occurring in Syria".
The recent opposition violence has resembled the infamous right-wing Guarimbas protests which blockaded streets in Febuary 2014 in an attempt to overthrow President Nicolas Maduro.
He retains the public support of the military - a pillar that analysts say could make him topple if removed.
Later that day, the president of a leading Venezuelan opposition party took refuge at the residence of the Chilean ambassador in Caracas and asked for protection. Capriles responded to the measure in a defiant speech to emotive supporters at a small Caracas sports arena, describing the measure as a desperate gambit of a decaying dictatorship.
The decision was later reversed amid widespread worldwide condemnation.
On Wednesday lawmakers, some still injured from the previous day's protest, began a symbolic process of removing Supreme Court justices. But that would require a green light from the attorney general, prosecutor general and comptroller, all Maduro allies.
Last week's court ruling led to an outcry from the worldwide community over what some countries said was a turn toward dictatorship.More news: Effort needed to lower tensions after tough talk over Gibraltar
"These people do whatever they want".
Ortiz was a 19-year-old student at a local university, the local mayor's office said.
A group of protesters eventually managed to march up to the metal police barricade, their hands in the air, and spray paint "Freedom" on it in blue letters.
The opposition says it faces growing persecution.
Protesters were assembling at seven designated points in capital city Caracas to march to a major highway. He is the first person to be killed in this round of protests.
Earlier this week, Mexican President Enrique Pena Nieto received leading Venezuelan opposition activist Lilian Tintori, the wife of jailed opposition leader Leopoldo Lopez, in a policy shift that reflects Mexico's increasing assertiveness against the government of Venezuela's President Nicolas Maduro.
Maduro has ruled out moving up the next presidential election, now scheduled for late 2018.
Regional governorship polls were postponed indefinitely in December and municipal ones are due later this year amid a chaotic political struggle.
The collapse in energy prices has sapped the country's revenues, prompting shortages of food, medicine and basic goods along with a surge in violent crime.
The center-right opposition has demanded a referendum on removing Maduro from power, but he has resisted and negotiations have broken down. He says it is due to a capitalist conspiracy backed by the United States.