An Iowa science teacher has been placed on leave after posting what appeared to be a threatening comment on social media aimed at young climate change activist Greta Thunberg before her planned visit to the state.

In an emailed statement to Fox News, the Waterloo Community School District said Friday that the Facebook post "rose to the level of putting this employee on administrative leave pending an investigation."

Local media have identified the teacher as Matt Baish, who is listed as a science teacher on Waterloo West High's website.

The post came ahead of the Swedish teen's planned visit to Iowa City for a student-led climate protest on Friday.

The post asked, "Who's all going?" to the event.

A user named Matt Baish responded, "Dont [sic] have my sniper rifle."

Iowa City police said security would be heightened for the event. Once the district was notified of the comment, a message was sent to school staff and families, district spokeswoman Tara Thomas told Fox News.

The district's social media policy warns staffers to "think twice before posting" and to not post "threats of physical or bodily harm."

Thunberg, 16, has made headlines for her calls for world leaders to take aggressive measures to combat the damaging effects of climate change.

Last month, she testified before Congress and denounced world leaders at a United Nations summit for an insufficient action plan on climate change.

"You are still not mature enough to tell it like it is. You are failing us," Thunberg said. "But the young people are starting to understand your betrayal.”

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The teen's blunt nature has also come under criticism. Russian President Vladimir Putin recently said that "no one has explained to Greta that the modern world is complex and different and … people in Africa or in many Asian countries want to live at the same wealth level as in Sweden."

During her appearance at the University of Iowa on Friday, she told a cheering crowd “as we all know, the U.N. Climate Action Summit was a failure," according to Reuters. “No matter what, we need to continue."