This post will be updated as the story develops.

At least eight people were killed on Friday after a shooter opened fire on students at Santa Fe High School in Texas. At least 12 others are being treated for injuries at local hospitals, including a police officer, according to local authorities.

The situation is still ongoing, as local officials say they may have located explosive devices on and nearby the campus.

#UPDATE 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. Call 911 if you see any suspicious item. #HouNews #SantaFeISD — Santa Fe ISD (@SantaFeISD) May 18, 2018

A suspect was arrested and another individual has been detained. Both are believed to be students.

One student told CNN that the fire alarm went off early Friday morning, prompting students to go outside when shots were fired. Others said that the shooter opened fire in the school’s art room, which prompted the alarm to later go off. The sequence of events remains unclear.

President Trump called the shooting a “horrific attack” during remarks he delivered at the White House Friday afternoon.

We grieve for the terrible loss of life, and send our support and love to everyone affected by this horrible attack in Texas. To the students, families, teachers and personnel at Santa Fe High School – we are with you in this tragic hour, and we will be with you forever… pic.twitter.com/LtJ0D29Hsv — Donald J. Trump (@realDonaldTrump) May 18, 2018

Texas Sen. Ted Cruz said that he and his wife Heidi were planning to pray for those affected by the shooting.

Heidi and I are keeping all the students and faculty at Santa Fe High School in our prayers this morning, along with all first responders on the scene. Please be safe and heed warnings from local officials. https://t.co/5Un3Y4IA86 — Senator Ted Cruz (@SenTedCruz) May 18, 2018

An unidentified man showed up shortly after the shooting with an American flag, carrying a handgun in a hip holster, saying that he was planning to walk to the school to “make America great again.”