UPDATE 2:05 P.M.
The governor of Texas, Greg Abbott, has confirmed that 10 people have died and 10 others were injured in the attack.
The shooter used a shotgun and a .38 caliber revolver, which the shooter likely took from his father. It's unclear if the 17-year-old shooter's father was aware.
The shooter is believed to have walked into the school with the shotgun under his trench coat.
UPDATE 12:10 P.M.
It's now being reported that 10 people, 9 students and 1 teacher, died in the shooting.
UPDATE 11 A.M.
A sheriff on the scene says there are 8-10 fatalities as a result of the shooting at Santa Fe High School in southeast Texas on Friday morning.
Multiple students were injured in a school shooting in southeast Texas early Friday morning.
KHOU and the Houston Chronicle are reporting that there are multiple deaths, with the latest report from KHOU saying eight people have died.
The active shooter situation unfolded around 7:30 a.m. at Santa Fe High School, which about 30 miles southeast of Houston.
The school announced on its Facebook page that the situation has been contained, but "there have been confirmed injuries."
How many students were injured and the extent of those injuries is unknown.
A student inside the school told ABC 13 that his friend pulled a fire alarm in an effort to alert students, after he saw a person with a gun walking through the hallway.
CNN last week published a list of all of the incidents that have resulted in at least one person being shot on school grounds in America in 2018, and there have been 21.
That includes 13 since the Parkland, Florida school shooting in February that killed 17.