"Fuck niggers" reads the message, followed by "fuck all porch monkeys," "whites only," "white America," and "Trump."

According to a Facebook post by Fred Ndip, the words were already there when his son arrived at school Wednesday morning.

"He does not feel safe at his own school any more," the father wrote. "I am not sure what to tell him!"

The post hit Facebook mid-afternoon Wednesday. Within hours, thousands were sharing his post on social media.

Osseo Area Schools spoksperson Barbara Olson confirmed the incident in a statement.

"We are horrified by it," it reads. "It goes against everything we stand for, and it is completely contrary to our core values as a district and individual schools.

Olson says an investigation is already underway and school leaders "will work very hard to identify who did this terrible act and to determine how they can support the students and staff who have been affected by it."