Matthew McConaughey, Sen. Ted Cruz respond to elementary school shooting in Uvalde, Texas

An 18-year-old gunman opened fire Tuesday at a Texas elementary school, killing at least 19 children as he went from classroom to classroom, officials said, in the latest gruesome moment for a country scarred by a string of massacres.

The attacker was killed by law enforcement.

The death toll also included two adults, authorities said. Gov. Greg Abbott said one of the two was a teacher.

An active shooter was reported at Robb Elementary School in Uvalde, Texas Tuesday, the Uvalde Consolidated Independent School District said in a statement on Twitter. The Uvalde Police Department said on Facebook that the shooter was taken into custody.

Uvalde is a city of about 16,000 people about 85 miles west of San Antonio.

It is the deadliest shooting at a U.S. grade school since the shocking attack in Sandy Hook, Connecticut, almost a decade ago, fueling a fresh round of grief and despair.

Texas leaders took to Twitter to respond to what occurred at the Texas school Tuesday.

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Matthew McConaughey: Action must be taken

Texas native Matthew McConaughey shared a statement on Twitter Tuesday: "As you all are aware there was another mass shooting today, this time in my home town of Uvalde, Texas. Once again, we have tragically proven that we are failing to be responsible for the rights our freedoms grant us."

"Action must be taken so that no parent has to experience what the parents in Uvalde and the others before them have endured. And to those who dropped their loved ones today not knowing it was goodbye, no words can comprehend or heal your loss, but if prayers can provide comfort, we will keep them coming."

Gov. Greg Abbott responds to Texas school shooting

Texas Gov. Greg Abbott tweeted Texans are grieving for the victims of this senseless crime and for the community of Uvalde.

"Cecilia & I mourn this horrific loss & urge all Texans to come together," Abbott said

Abbott says the suspected shooter, an 18-year-old man, also died and was believed to be killed by responding officers.

Abbott says the shooter had a handgun and possibly a rifle.

He also directed the Texas flag to be immediately lowered to half-staff statewide, in memory of those who lost their lives in the shooting.

Ted Cruz: Thank you to heroic law enforcement

Sen. Ted Cruz thanked law enforcement and first responders on Twitter for acting so swiftly at the elementary school.

"Heidi & I are fervently lifting up in prayer the children and families in the horrific shooting in Uvalde. We are in close contact with local officials, but the precise details are still unfolding," Cruz tweeted.

Beto O'Rourke: Broken hearts are with Uvalde

Democratic gubernatorial candidate Beto O’Rourke joined Texas leaders to respond to the tragic shooting that occurred Tuesday. O' Rourke said, "our broken hearts are with Uvalde."

O'Rourke also tweeted that Abbott "made it easier to carry guns in public."

"The moment to stop Uvalde was right after Sandy Hook. After Santa Fe High. After El Paso. The moment to stop the next slaughter is right now," O'Rourke tweeted.

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Veronica Escobar: Deeply saddened this has happened again

Rep. Veronica Escobar, D-El Paso, was deeply saddened by the shooting in Texas and said "no child should have to experience this, and no parent or teacher should live in such fear."

Escobar sent a second tweet after the 15 deaths were confirmed, "To my colleagues who refuse to act, when is it finally enough? It’s time for you to join us in passing gun violence prevention legislation."

LeBron James responds to Texas elementary school shooting

NBA superstar Lebron James sent his thoughts and prayers to the families affected by the shooting.

"Like when is enough enough man!!! These are kids and we keep putting them in harms way at school. Like seriously "AT SCHOOL" where it's suppose to be the safest!"

El Paso leaders respond to Uvalde school shooting

El Paso Mayor Oscar Leeser sent his prayers to the family members and everyone in Uvalde as they deal with "this senseless act of violence."

"Our hearts break in El Paso for the children and teacher lost in the shooting in Uvalde, Texas. It is particularly shattering that the most innocent of souls were targeted," Leeser said.

El Paso County Judge Ricardo Samaniego said "we have to begin to address where this hatred and evil stems from in our society."

"I can not imagine the pain that comes from losing a child and the overwhelming despair the community of Uvalde is feeling," Samaniego said.

El Paso District Attorney Yvonne Rosales said the "unbearable loss of life will affect the community of Uvalde for generations to come, as it has here in El Paso."

"May the memories of those who lost their lives today always be remembered. El Paso stands behind the community of Uvalde," Rosales said.

USA Today and Associated Press contributed to this report

This article originally appeared on El Paso Times: Uvalde, Texas shooting: Ted Cruz, Lebron James respond on Twitter