Florida high school alumni send moving video to shooting survivors

— -- Alumni of the Florida high school where 17 students and teachers were killed in a deadly shooting rampage created a moving video with messages of support for the survivors.

"We have a message for the world," the video begins, before launching into the series of supportive speeches.

"I just want you to know that thousands of Stoneman Douglas alumni are standing with you," Stuart Siegel, senior class president of Marjory Stoneman Douglas High School's founding class of 1992, said. "We’re so proud of the way that you’re handling this unspeakable tragedy."

The video was also directed by an alumnus -- Ryan Blitzer, who graduated in 2013 from the Parkland, Florida, high school.

A former Marjory Stoneman Douglas student, Nikolas Cruz, is accused of fatally shooting 17 people at the school on Valentine’s Day. Among the killed were 14 students, along with the school’s athletic director, an assistant football coach and a teacher.

The newly-released video includes messages from alumni living all over the country, from San Francisco to Louisiana to Boston.

"Stay strong Eagles," one alumnus says in the video, referring to the school’s mascot.

Some of the alumni’s messages allude to the outspoken role Marjory Stoneman Douglas students have played in advocating for gun reform after the shooting. Students traveled by bus from Parkland to the state capitol in Tallahassee as part of the “Never Again” movement spawned by the mass killing.

They have also organized a walkout on March 14th for 17 minutes to honor the lives lost and plan to attend the "March for Our Lives" in Washington, D.C., next month.

"Change has to happen and Douglas is going to be the school that makes it happen. Eagle pride," a member of the school’s graduating class of 2012 said in the video.

Blitzer told ABC News the video includes messages of support from alumni of every graduating class of Marjory Stoneman Douglas. He said the alumni mobilized through social media and have since created a website, msdstrongalum.com, and organized a national petition calling for an end to gun violence in the U.S.

The video includes messages of support from the school’s principal and two current teachers who spoke about the school’s motto: "Be positive, be passionate and be proud to be an Eagle."

The video concludes with a stirring quote from the school’s namesake, the late Marjory Stoneman Douglas, who was a journalist, activist and environmentalist: "There is always the need to carry on."

ABC News' Shaun Francis and Bill Hutchinson contributed to this report.