A racist online message threatening to murder students at Howard University has led to fear and class cancelations at the historically black school.

"Any n—r left at Howard University after [10 a.m. Thursday] will be the first to go," the message, apparently posted to the online forum 4chan,  which is known as a hang-out for trolls, hackers and other online mischief-makers, reads. The message continued, "It's not murder if they're black."

The only version of the message available is a picture of a printed-out version of the threat.

Caution: image contains racist slurs and hate speech. Click here to read the letter.

The school's president, Wayne Frederick, released a letter Thursday saying the D.C.-area college was aware of the the threat and was working with campus, local and federal law enforcement.

"In an abundance of caution, the University has increased security on campus and at area metro stations," Frederick wrote.

Related link: UPDATE: Local university threat appears on internet forum 

While campus appeared to still be open, some students posted images on Twitter of emails from professors canceling their classes on Thursday.

The person who wrote the anonymous message, posted Wednesday around 7:30 p.m. on Wednesday, claims they left Missouri University, where recent protests over alleged racism on campus have garnered national attention and led to the resignation of the university's president.

"I left MU yesterday because I couldn't put up with it anymore. I go home to MD and what do I see? The same old s—t," the threat reads. "Sure, the po po will take me down, but I'll go out a hero knowing I made the world better."

Related link: UPDATE: Suspect in custody after gun prompts CCP lockdown

Supporters and students took to social media to speak out about the threat.

"I'm crying out of fear. I shouldn't have to fear for my brother's life while he's at school. Be safe y'all #HUStrong," tweeted one.

Others criticized the decision to keep school open.

"So what happens when administration doesn't take threats seriously and something happens?"  another person tweeted. 

Philadelphia universities were recently on high alert after a similar threat of violence was made by a poster on 4chan. No incidents of violence were reported.