UPDATE: 3:19 p.m. EST Police recovered two guns from the suspect -- a shotgun and a .38 caliber revolver, which, according to Gov. Greg Abbott, were legally purchased by the suspect's father, reported Stephen Gutkowski of the Free Beacon.
UPDATE: 1:06 p.m. EST The suspect in custody is a 17-year-old male student, CNN reports.
UPDATE: 12:41 p.m. EST Santa Fe ISD Police Chief Walter Braun confirmed that explosive devices were found at the school and surrounding areas, according to CNN.
UPDATE: 12:35 p.m. EST The number of fatalities is believed to be fewer than 10, but is still not fully confirmed at this time, according to Santa Fe ISD.
UPDATE: 12:24 p.m. EST Santa Fe ISD tweeted: "Possible explosive devices have been located at the school and off campus. Law enforcement is in the process of rendering them safe. School has been evacuated."
UPDATE: 12:15 p.m. EST CNN reports at least 12 people are hospitalized with injuries at multiple hospitals. Police are searching for additional victims in the school, as well as for explosives.
UPDATE: 12:08 p.m. EST Harris County Sheriff Ed Gonzalez addressed media, saying that both the suspect and a person of interest in custody are believed to be students at Santa Fe High School.
UPDATE: 12:01 p.m. EST Harris County Sheriff Ed Gonzalez said one police officer was injured and is being treated. The extent of his injuries is unknown right now. CBS News reported that a school resource officer was also injured.
ORIGINAL POST: Multiple people were shot and killed at a Texas high school Friday morning, after a gunman reportedly opened fire in a classroom, according to police.
At least eight people have been reported dead, according to police, with more people reported as injured at Santa Fe High School in Santa Fe, Texas. Helicopters were on the scene to transport some victims to the hospital.
A suspect has been arrested, and a second person has been detained as well, and the students have evacuated the school and are attempting to reunite with parents.
Students were evacuated "following the same procedure as a fire drill," one student told CNN.
"As soon as the alarms went off, everybody just started running outside," 10th-grader Dakota Shrader told reporters, "and next thing you know everybody looks, and you hear boom, boom, boom, and I just ran as fast as I could to the nearest floor so I could hide, and I called my mom."
A witness reported that an armed person entered an art class and began shooting. The witness said it looked like a shotgun, but that has not been confirmed. Law enforcement has yet to reveal any information about the type of weapon used.
Santa Fe is about 30 miles southeast of Houston.
This is a developing story and will be updated.