Updated Feb. 21, 2014 5:13 p.m. ET
CARACAS, Venezuela—Day after day since early this month, on streets clouded with tear gas, William Colmenares and other young Venezuelans raise their voices against President Nicolás Maduro's government. They accuse him of acting like a dictator and wrecking the country's economy.
Mr. Maduro calls the protesters fascists, part of a plot by the U.S. government to derail Socialism in this oil-rich country, and his government has arrested dozens.
Students and opposition leaders say that National Guard troops have fired rubber bullets and clubbed some protesters. State security agents, along with motorcycle gangs of militant supporters of the ruling Socialist party, have also fired live ammunition on crowds, witnesses have said.
Six people have been shot dead since Feb. 12, including a local beauty queen, from the ranks of a surging opposition movement.
Yet that hasn't deterred Mr. Colmenares and other young people—from high-school and university students to recent graduates looking for work in a moribund economy. They form the backbone of an increasingly raucous movement that has become the most formidable challenge the president has faced since taking office in April 2013.
"I had to come out after all that violence," said Mr. Colmenares, who is 23 years old and works in a department store, referring to the first outburst of deadly gunfire.
"As long as there is repression, we will keep coming out," he said. "And something horrible is bound to happen again."
Attorney General Luisa Ortega on Friday said eight people had died as a result of the protests, including a woman who died of a heart attack in an ambulance stuck in traffic.
An additional 137 people have been injured, she said. Some 24 people are in jail and dozens more free on bail pending legal action. Opposition sympathizers estimate the numbers of arrests and injured are much higher.
Many of the demonstrators are so young that they have known only Chavismo, the ruling system named after the late President
Hugo Chávez who came to power in February 1999 and transformed Venezuela into a Socialist state closely aligned to Communist Cuba. They have spent their formative years listening to lofty Chavismo rhetoric—only to see their prospects dim as the country sinks further into economic crisis.
Many of Mr. Maduro's top aides have said the protests are led and organized by rich children of the country's elite and middle class, funded out of Miami and Bogotá. "The tough guys of fascism are out in the streets looking down on the people, kicking people in the streets, destroying public property, firing at apartments," Mr. Maduro said on television Thursday.
Those claims sound hollow to people like José Materano, 21, whose parents work for the government. He attends a state university but says he is tired of living in a country with inflation of about 60%, the highest in Latin America, and widespread food shortages.
Mr. Materano lives with his parents in a hillside slum—the kind of place where Mr. Chávez built his following. His parents were Chavistas, and he was taught as a boy to revere the presidential palace, which can be seen from the slum. That drove him to study law enforcement, which he hopes he can use to protect the country one day, he said.
But, he added, he also has seen how his parents' combined salaries haven't been enough to move them out of their crumbling home, which mirrors the crumbling of their support for the government.
"They don't dare speak out against the government because they would lose their jobs," Mr. Materano said. "They are even pushed to attend government rallies."
Mr. Materano said he wasn't particularly political until late last year, with consumer prices rising at breakneck speed and supermarket shelves increasingly bare of basics. "There is no cooking oil, no sugar, no rice, no toilet paper. Venezuela isn't making anything except [petroleum]. Where is all that money going?"
In 1958, Marcos Pérez Jiménez, the longtime dictator, was toppled in a popular uprising that began with student strikes. A wave of massive protests in 2002 resulted in Mr. Chávez being briefly ousted from office.
More recently, in 2007, students—many of them from the Central University of Venezuela—led a series of street protests and rallies against a referendum that would have rewritten the constitution to give Mr. Chávez more powers. The referendum was voted down.
The current protests, which range day by day from several hundred to tens of thousands, are far smaller. They began after the alleged attempted sexual assault of a university student on Feb. 2, and then spread. The government reacted by arresting protesters, triggering more outrage.
But they come at a time when Venezuela's economy is seriously dysfunctional, said Demetrio Boersner, a former diplomat in the Chávez government and a historian who has written frequently about politics here.
He said the protests could energize the opposition, which had become resigned to having little voice and few options.
"The fact that the students have come out into the streets has brought a sort of psychological release, and people are starting to have hopes that things might change," Mr. Boersner said.
Javier Corrales, an Amherst University professor who has written a book about the political system here, said that the young people present a particularly prickly challenge to the government because they cannot be easily typecast as oligarchs, fascists and "parasitic bourgeoisie," as Mr. Maduro frequently labels critics.
"The government is at a loss of words for dealing with them," said Mr. Corrales. "They government cannot easily justify its belligerent attitude since these challengers emerge in ways that defy the government's traditional enemy categories."
At the same time, Mr. Corrales said that the uprising benefits the government in one important way: the divisions apparent in Chavismo can unite because of the threat. "Now, Chavistas can focus on one common goal, surviving this attack, and this inevitably produces a centripetal force within the ruling party toward Maduro."
Between Feb. 7 and Feb. 14, Mr. Maduro's approval rate tumbled more than 10 percentage points, to 41.5% from 52%, according to Luis Vidal, director of Caracas-based research firm More consulting.
"You are seeing this loss of support among people who identify themselves as independent or swing voters because of the government's response to the marches," Mr. Vidal said. But he agreed that the president was consolidating support among hard-core supporters of the ruling party.
"He has framed the protests as protest against him and the legacy of Hugo Chávez and not against the problems of the country," he said.
María Mendez, a 19-year-old marketing student who comes from a family of government supporters, said she joined the protests because she was tired of scouring multiple grocery stores each day looking for milk to feed her infant daughter.
"I go to school and I work, so I don't have time to stand in a line at a supermarket for hours," she said during a recent rally. "I'm so sick of it. People are tired of the crime and food shortages. We are tired of this government."
Many students say that a common topic of conversation is whether they will stay in Venezuela, a country that once was a destination for immigrants, or try to leave for another country, where job prospects are better and public safety more secure. Lines of visa-seekers at local embassies have grown.
"The situation is really bad, brother, in all aspects," said Edwin González, a law student who has been among the hundreds of hard-line demonstrators who have made Altamira Plaza in eastern Caracas the rally point for daily protests. "The economy is a mess, you can't leave your house because you might get murdered or robbed, the devaluations have made our money worthless. With Chávez things were bad but things have nose-dived with Maduro."
José Francisco Rodríguez, a 21-year-old law student, said he would like to get married but all the uncertainty has kept him from popping the question to his girlfriend. If the protests don't bring about a change, he would reluctantly consider leaving the country, said Mr. Rodriguez, a fluent English speaker.
"But I still have that flame of hope inside me that we can bring a change here," he said. "I'm going to try at least."