Santa Fe High School

At least 8 dead in shooting at Santa Fe High School in Texas, explosives found on campus: Officials

At least eight people are dead after a student allegedly opened fire at Santa Fe High School in Texas this morning, sending students fleeing for their lives, Harris County Sheriff Ed Gonzalez said.

The number of deaths "could be anywhere between eight to 10, majority being students," Gonzalez said.

The shooting was contained and the school was evacuated, but explosive devices have also been found at the school and in surrounding areas, authorities warned.

Community members are warned to be on the lookout for suspicious items, officials said.

This morning's shooting took place in an art class, witnesses said, ABC station KTRK in Houston reported.

"I heard the [fire] alarms and everybody ran out,” tenth-grader Dakota Shrader told KTRK. “At first all we heard was ‘run, run,’ and next thing you know we hear, ‘boom, boom, boom.’”

Michael Ciaglo/Houston Chronicle via AP

A man hugs a woman outside the Alamo Gym where parents wait to reunite with their children following a shooting at Santa Fe High School in Santa Fe, Texas, May 18, 2018.more +

Michael Ciaglo/Houston Chronicle via AP

Santa Fe High School freshman Caitlyn Girouard, center, hugs her friend outside the Alamo Gym where students and parents wait to reunite following a shooting at Santa Fe High School, May 18, 2018, in Santa Fe, Texas.more +

“Everybody started running,” she said, “and I tried to make it to the safest place that I could as fast as I can. I called my mom right away.”

“She couldn’t breathe, she was having an asthma attack,” her mom added. “I didn’t even know where to find her.”

Michael Ciaglo/Houston Chronicle via AP

A woman prays in the grass outside the Alamo Gym where parents wait to reunite with their kids following a shooting at Santa Fe High School, May 18, 2018, in Santa Fe, Texas.more +

HCSO/via Reuters

Law enforcement officers are responding to Santa Fe High School following a shooting incident in Santa Fe, Texas.

One male is in custody and a second individual, a person of interest, has been detained, Gonzalez said, adding that both are students.

At least 11 people were transported to hospitals, including a police officer, officials said.

Among the injured are two people in critical condition, officials said.

Kevin M. Cox /The Galveston County Daily News via AP

Police officers in tactical gear move through the scene at Santa Fe High School after a shooting on May 18, 2018, in Santa Fe, Texas.

KTRK-TV ABC13 via AP

A shooting was reported at Santa Fe High School, May 18, 2018, in Santa Fe, Texas.

As students lined up outside the building, ambulances, helicopters and federal agents swarmed the school in Santa Fe, between Galveston and Houston.

ABC News

A shooting took place at Santa Fe High School in Texas, May 18, 2018.

Kevin M. Cox /The Galveston County Daily News via AP

Emergency responders from multiple agencies work at the scene in front of Santa Fe High School in response to a shooting, May 18, 2018, in Santa Fe, Texas.more +

President Trump, Parkland students react to Texas school shooting

"I’m scared to even go back," said one student, crying. "It’s just not something that you should feel throughout the day, being scared. Especially somewhere where we say the Pledge of Allegiance."

“It has been happening everywhere. I wasn’t surprised it happened here,” one student told KTRK. “I was just scared. I just kept running.”

KTRK

Santa Fe High School students leave the school after a reported shooting, May 18, 2018 in Santa Fe, Texas.

Today's shooting comes three months after the Parkland, Florida, high school shooting that killed 17 students and staff. The Parkland massacre prompted a massive, youth-led push for school safety and gun reform.

Just last month students at Santa Fe High School participated in a nationwide school walkout against school gun violence. The walkout was held on April 20 -- the anniversary of the 1999 Columbine High School massacre that killed 13.

A Santa Fe student said they read poems by a Parkland survivor, held 17 minutes of silence in honor of the 17 people killed in Parkland, and discussed ways they could raise gun violence awareness and make their voices heard.

mukethemusical/Twitter

Students at Santa Fe High School participated in a nationwide school walkout against school gun violence, April 20, 2018.

School shootings have "been going on too long in our country," President Trump said today from the White House.

"Too many years, too many decades now, we grieve for the terrible loss of life and send our support and love to everyone affected by this absolutely horrific attack," he said.

"My prayers are with each student, parent, educator and first responder impacted,” Education Secretary Betsy DeVos said in a statement. “Our schools must be safe and nurturing environments for learning. No student should have to experience the trauma suffered by so many today and in similar events prior.”

“We simply cannot allow this trend to continue,” she said. “Every day, the Federal Commission on School Safety is working to identify proven ways to prevent violence and keep our students safe at school. Our work remains urgent. Our nation must come together and address the underlying issues that lead to such tragic and senseless loss of life."

Gov. Greg Abbott ordered Texas' flags to fly at half-staff across the state.

ABC News' Josh Margolin, Jack Date, Aaron Katersky, Jennifer Watts, Jonah Lustig, Alyssa Pone and Laura Coburn contributed to this report.