(CNN) "We lost 17 lives on Valentine's Day. That's supposed to be the international day of love," Marjory Stoneman Douglas High School principal Ty Thompson said in an emotional video message posted on Saturday, three days after a gunman went on a shooting rampage at the Parkland, Florida, school.

"We're going to take the love that we got lost on Wednesday and we're going to spread that over the next days, weeks, months and maybe even years."

Thompson took the time to thank authorities and first responders for their help in responding to Wednesday's school shooting

"My heart is breaking for the victims' families, and our entire Stoneman Douglas community," said Thompson.

He thanked the staff and students for what he called "heroic efforts." He added that the school had practiced protocols for these situations regularly, and that he thinks lives were saved as a result.

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