MEXICO CITY — A spontaneous student movement is bringing attention to allegations that Mexico’s media conglomerates offer biased and superficial election coverage, drawing a whiff of “Mexican spring” to a lackluster presidential campaign.

The movement has gathered steam through Twitter and Facebook, leading to student marches in the capital and half a dozen other cities across Mexico.

“Down with Televisa!” and “This is not a soap opera,” a throng of students chanted Wednesday night as they marched along Mexico City’s central boulevard.

Voters will head to the polls July 1, and opinion surveys find that Enrique Pena Nieto, the telegenic candidate of the once-dominant Institutional Revolutionary Party, or PRI in its Spanish initials, is a runaway favorite to carry the party back to power after 12 years in the opposition.

The two Mexican media conglomerates that dominate the airwaves, Televisa and TV Azteca, have offered broad, and in some cases fawning, coverage of Pena Nieto’s campaign while the nation’s biggest newspaper chain, the owner of El Sol de Mexico, has been an open-throated cheerleader.

Many of the university students taking to the streets were only youngsters when Pena Nieto’s PRI was at the end of a 71-year monopoly on power in 2000.

Yet their protests, which began at a rowdy event May 11 at which students at the elite Jesuit-run Iberoamerican University jeered Pena Nieto, have added “a sense of urgency” to an election season that until now had been lethargic, economist Arturo Franco wrote Thursday on the website animalpolitico.com.

“It is cause for reflection,” he wrote. “Is this movement the beginning of something bigger? Will it mark an awakening in Mexico? Or is it a momentary curiosity?”

After the May 11 university event, Televisa gave only slight coverage to the student rebellion and El Sol de Mexico carried a banner headline that suggested infiltrators from outside the university were behind the disruptions.

In response, indignant students posted a YouTube video in which 131 of them showed their student ID cards, defending their right to express their views. Thus began a campaign under the slogan “We are more than 131,” and the Twitter hash tag #YoSoy132 – “I Am 132” – trended sharply upward.

Student protesters rallied last Friday at the headquarters of Televisa and took to the streets Wednesday evening, with some 10,000 gathering at the Stele of Light, a recently completed giant monument, before marching down the capital’s Paseo del la Reforma boulevard to the landmark Angel of Independence monument.

“It’s really something that students would start from scratch to organize this,” said Alejandro Mora Ruiz, an 18-year-old high school student.

“We’re fed up with media that hide real information,” echoed Berenice Marin, who was nearly drowned out by chants among students from at least 15 private and public universities in the capital. She said the movement was nonpartisan.

Alejandro Calvillo, the head of the nonpartisan activist group Power to the Consumer, said the student movement was having an effect, noting that Televisa aired longer images of the Iberoamerican University event this week, 10 days after it unfolded.

“These are the strongest protests against the television monopolies that have ever occurred,” Calvillo said, adding that Televisa and TV Azteca felt pressure to begin covering the student movement.

Protests also were organized in Puebla, Tijuana, Guanajuato, Monterrey and in the State of Mexico, where Pena Nieto recently served as governor.

A student petition read at the protest Wednesday night called for regulators to open “real competition” of the television spectrum, demanded that ombudsmen be installed at major media outlets to ensure fairness and exhorted authorities to force TV networks to carry a June 10 presidential debate.

TV Azteca declined to air the first debate May 6.

Neither network offered immediate reaction to the protest movement, although Emilio Azcarraga, the chairman of Televisa, tweeted earlier this week that “At Televisa, we value young people and we listen to their opinions. We will always be open to them.”

Through its dozens of stations and repeater towers, Televisa enjoys roughly a 70 percent share of the television viewing audience in Mexico, while TV Azteca holds all but around 5 percent of the remainder.

Census information shows that of Mexico’s 80 million potential voters, 14 million have never voted in a presidential election because of their youth.

Word passed on social networks Thursday for students to gather again Saturday in Mexico City’s Tlatelolco district.

Obscure political forces, meanwhile, seem intent on trying to quell the student movement, which appears to have no identifiable organizers.

In a statement published Thursday, the head of the Iberoamerican University, Jose Morales Orozco, said students at his university who took part in the “We are the 131” video “have received intimidating telephone calls and threatening messages in social media” and that the private university would take action to protect them.