Texas Gov. Greg Abbott says 10 people are dead and 10 more wounded after a shooting at a high school in the town of Santa Fe, the nation's deadliest such attack since the massacre in Florida that gave rise to a campaign by teens for gun control.

Several law enforcement officials told NBC News that nine students and one teacher died in the shooting.

Abbott called Friday's shooting "one of the most heinous attacks that we've ever seen in the history of Texas schools."

The governor said the suspect had a shotgun and .38 revolver, which appeared to be legally owned by the suspect's father. He says explosive devices including a molotov cocktail that had been found in the suspected shooter's home and a vehicle as well as around the school and nearby.

A law enforcement official told NBC that four pipe bombs were found inside the school. Officials said, however, that none of the devices exploded and that it wasn't clear whether any of them were fully capable.

The governor says the suspect said he originally intended to commit suicide but gave himself up and told authorities that he didn't have the courage to take his own life.

Abbott said there are "one or two" other people of interest being interviewed about the shooting.

The governor said there were few prior warnings about the suspected gunman, unlike in other recent mass shootings.

Galveston County Sheriff Henry Trochesset says 17-year-old Dimitrios Pagourtzis has been charged with capital murder.

Abbott said that "unlike Parkland, unlike Sutherland Springs, there were not those types of warning signs." He was referring to the Feb. 14 school shooting in Florida and one in November inside a church in a town near San Antonio.

Abbott says "the red-flag warnings were either non-existent, or very imperceptible" in the case of the suspected Santa Fe shooter.

A woman who answered the phone at a number associated with the Pagourtzis family declined to speak with the AP.

She said: "Give us our time right now, thank you."

Pagourtzis plays on the Santa Fe High School junior varsity football team, and is a member of a dance squad with a local Greek Orthodox church.

@SheriffEd_HCSO: On the scene now. No longer an active situation. Personnel treating the injured. Info is still preliminary, but there are multiple casualties. @HCSOTexas is on the scene with other law enforcement assisting in the search of the school.

A hospital spokesman says a school resource officer who was shot in the arm when he engaged the gunman is undergoing surgery.

David Marshall, the University of Texas Medical Branch's chief nursing officer, says Santa Fe school resource officer John Barnes is in stable condition Friday afternoon.

Marshall says a bullet hit Barnes' arm, damaging the bone and a major blood vessel around his elbow. He says the blood vessel has been repaired, and that Barnes is expected to emerge from surgery within a few hours.