Another responded to conservative personality Tomi Lahren, who advised against "lecturing" Texas residents on guns. "10 of my classmates died yesterday and 10 others were injured," student Bree Butler wrote. "i would LOVE to lecture any texan on gun laws."
It's the second such instance just this year of school shooting survivors’ using social media to draw attention to gun violence.
In the aftermath of the Parkland school shooting in Florida in February, numerous students spoke out on Twitter and other platforms, ultimately attracting hundreds of thousands of followers.
Parkland students like David Hogg and Emma Gonzalez organized a national march on gun violence in March and have continued to use their accounts to advocate for political action, including registering voters for the 2018 midterms and calling for boycotts on firms that invest in gun manufacturers.
In the wake of the shooting Friday morning that killed 10 people and wounded 13, Texas Gov. Greg Abbott promised to work to find "solutions."
But for a number of students, the pledges are too little, too late. "We want change not sympathy," Santa Fe student Kara Hitchcock wrote.
Kennedy Rodriguez went after Texas Lt. Gov. Dan Patrick, who suggested during a news conference Friday that Texas should reconsider school designs to reduce unguarded entrances and exists. "Screw you," Rodriguez responded, with the hash tag #VoteThemOut.
Others publicly called out Trump for his multiple tweets over the weekend on the Russia probe and other matters.
"Have you considered putting your 'witch hunt' on hold for a few days?" asked ninth-grader Brooklynn Butler, Bree's sister. "10 people were killed in a shooting that took place in the country you are in charge of and you haven’t mentioned anything about them except for the fact that they’re in your prayers. please take action."
Your "thoughts and prayers aren’t going to fix the problem we face as a country," tweeted 12th grader Tyler Cruz. "We need action to combat this ever growing issue. WE NEED CHANGE."
Not all were overtly political. Some of the students' posts simply mourned the sense of normality and peace that had been shattered when the gunman opened fire:
But amid the despair, a touch of the optimism expressed by the Parkland students over the ability of their efforts to effect change has been evident as well. "The young people will win," Rodriguez tweeted.
ABC News’ Allison Pecorin and Fergal Gallagher contributed to this report.