When U.S. mom Stacey Feeley snapped a photo of her three-year-old standing on top of a toilet, she did it with the intention of sending it to her husband to show what their "mischievous" daughter was up to.

When the young girl told her mom she was actually practising a lockdown drill, and preparing for what she would have to do if she were stuck in a bathroom, Feeley said she "broke down."

"At that moment all innocence of what I thought my three-year-old possessed was gone," the Michigan mom wrote in a Facebook post that accompanied the photo of her daughter on June 15.  

The post has since been shared more than 12,000 times and has garnered attention in the U.S. and overseas.

The young girl, Feeley said in her Facebook post, had gone through the lockdown drill at her preschool.

The post seems to have struck a chord online as it follows the worst mass shooting in U.S. history in which a gunman opened fire at an Orlando nightclub, leaving 49 people dead.

Feeley said after walking in on her daughter practising the lockdown drill, it took her a moment to "grasp the scale" of what children in America face today.

"When you see it right in your face, an innocent little kid, and you see how they're going to grow up in society, it totally took me aback," she told CTVNews.ca in a phone interview from Michigan.

Feeley said she's concerned about gun control in the U.S., and she has signed petitions and written to her senators advocating for stricter regulations around gun ownership.

"But it just seems like nothing is working," she said.

On Monday, the U.S. Senate rejected proposals aimed at keeping extremists from acquiring guns and reforms around background checks for firearms purchases.

In her Facebook post, Feeley asked American politicians to take note of what the country's children are learning in schools.

"They will live their lives and grow up in this world based on your decisions," she wrote. "They are barely 3, and they will hide in bathroom stalls standing on top of toilet seats. I do not know what will be harder for them? Trying to remain quiet for an extended amount of time or trying to keep their balance without letting a foot slip below the stall door?"

She also advocates for "smart technology" to create safer guns and more support for those suffering from mental illness.

"I cannot give you techie advice, expertise in healthcare, or financial backing, BUT maybe I can point you in the right direction? Maybe I know someone who knows someone who can help?" she writes

The viral post has sparked a mixed reaction.

Most commenters were supportive of efforts to improve gun control in the U.S.

However, a number of commenters used the post to decry any type of legislation that would lead to more gun regulation in the U.S.

Feeley said she's not surprised by the divisive comments on her post.

"This particular amendment, it brings with it a lot of these extremist attitudes," she said. "Which, in my eyes, are almost as extremist as the people committing some of these acts."

Feeley said she hopes the photo can make even "a shred" of a difference when it comes to the gun debate in the U.S.

"I want a world where my daughter is still safe, where she is not going to be worried about going Disneyland."