A US kindergarten has taught its young students what to do in the event of a shooting - in the form of a chilling nursery rhyme.
Georgy Cohen from Somerville, Massachusetts, posted a photo of the poem to Twitter.
"This should not be hanging in my soon-to-be kindergartner's classroom," she wrote.
The rhyme, which is meant to be sung to the tune of 'Twinkle Twinkle Little Star', turns a terrifying experience into something a young child could understand.
Lines include: 'Go behind the desk and hide, wait until it's safe inside'.
Many on social media were horrified by the need for such a poem in a kindergarten.
However local mother Saba Bazzaz told WBZ-TV that she thinks the rhyme is a good way to teach children how to best protect themselves.
"It's not scary. Just in case they really need to do it, the kids can rhyme to the song and do what's needed to be done," she said.
Somerville Mayor Joseph Curtatone and school superintendent Mary Skipper said in a statement that the poem was sadly necessary because of the country's high number of mass shootings.
"As much as we would prefer that school lockdowns not be a part of the educational experience, unfortunately, this is the world we live in," they said.
"It is jarring - it's jarring for students, for educators, and for families."
"This poem is an example of how one of our educators used a rhyme to help her young students stay calm and remember the key steps they would need to follow during a drill or real emergency."
In 2012, 20 children, all aged between six and seven years old, were killed by a gunman at Sandy Hook Elementary School in Connecticut.