Uvalde, Texas - Residents of Uvalde, Texas, gathered on Sunday to march for gun control in the aftermath of a mass shooting that left 21 people dead at a local elementary school.

Several hundred people hit the streets in Uvalde, Texas, on Sunday to demand greater action to curb gun access in the wake of the shooting at Robb Elementary.

The protest, called the Unheard Voices March and Rally, was organized by Javier Cazares, father of nine-year-old victim Jackie Cazares, Texas Public Radio reported. Texas' Democratic nominee for governor Beto O'Rourke was in attendance.

"Not one more child! Not one more child! Not one more child!" the crowd chanted as they marched. Many held signs with messages like "Hear their Screams" and "You Don't Need a Gun to Be Powerful."

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The march came after an 18-year-old gunman entered Robb Elementary and killed 19 children and two adults. He purchased his firearm legally.

Uvalde police have been criticized for their delayed response to news of the shooting, with the Justice Department opening an inquiry into law enforcement's conduct.

The attack renewed nation-wide cries for stricter federal gun control laws, including a ban on assault weapons.

Family members of the victims took the mic to share their messages with the gathering protesters, demanding change for the state and the country.

"A war weapon is more important to our current governor than the lives of his people," Faith Mata, sister of 10-year-old Tess Marie Mata, said of Republican Governor Greg Abbott.

Vicente Salazar Sr., grandfather of 11-year-old Layla Salazar, said, "We cannot keep this under the rug no more. There's too many people that got hurt here and are still grieving, because I know I grieve every single night for these children, including my own granddaughter."

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"With that said, we have to have the courage to march on, so let's do it for the right reasons. Let's vote for the right reasons and not the pocketbook," Salazar urged the crowd. "Please, people, we need to get out and vote."

For those asking how they can help, Angel Garza, stepfather of 10-year-old Amerie Jo Garza, had a clear, powerful message: "Join us! Please, help us change this!"