A 17-year-old student wearing a trench coat and armed with a shotgun and pistol has opened fire at his high school in Texas, killing nine students and a teacher before surrendering to officers.
Santa Fe High School, southeast of Houston, on Friday joined a long list of US campuses where students and faculty staff have been killed in mass shootings.
The gunman opened fire in a morning art class in his Houston-area high school, killing 10 people and wounding another 10, with several of them in critical condition.
Authorities have identified the suspected offender as Dimitrios Pagourtzis.
It was the fourth-deadliest mass shooting at a US public school in modern history, and again stoked the nation's long-running debate over gun ownership three months after 17 teens and educators were fatally shot in Parkland, Florida.
"I wanted to take care of my friends, but I knew I had to get out of there," said Courtney Marshall, 15, who was in the art class, adding that she saw at least one person hit. "I knew the guy behind me was dead."
Two school officers engaged the shooter, including school district police officer John Barnes, who was in critical condition after a gunshot wound to his elbow that almost caused him to bleed out, hospital officials said.
Authorities have not made public details of how they engaged the shooter.
A vigil was held on Friday night for the victims, who have not been officially identified.
National Football League star J.J. Watt, who plays defensive end for the Houston Texans, said he will pay for the funerals for the deceased, local media reported.
Classmates described Pagourtzis as a quiet loner who played on the football team.
On Friday, they said he wore a trench coat to school in Santa Fe, about 50km southeast of Houston, on a day when temperatures topped 32 degrees Celsius.
Texas Governor Greg Abbott said Pagourtzis obtained firearms from his father, who had likely acquired them legally, and also left behind explosive devices.
"Not only did he want to commit the shooting, but he wanted to commit suicide after the shooting," Abbott told reporters, citing a police review of the suspect's journals. "He didn't have the courage to commit suicide."
Pagourtzis was charged with capital murder and denied bail at a brief court hearing later on Friday, where he appeared in handcuffs and wearing a green prison jumpsuit. He spoke in a soft voice and said "Yes, sir" when asked if he wanted a court-appointed lawyer.
Pagourtzis spared people he liked so he could have his story told, a charging document obtained by Reuters showed.
Abbott said investigators had seen a T-shirt on the suspect's Facebook page that read "Born to Kill," and authorities were examining his journal. But there were no outward signs he had been planning an attack, he said.
It was the second mass shooting in Texas in less than a year. A man armed with an assault rifle shot dead 26 people during Sunday prayers at a rural church last November.
