The posters coincided with a speech introducing the school's Antiracist Research and Policy Center.
"We are well aware this act occurred the same evening Dr. Ibram Kendi presented 'A Vision for Equality,' an introduction to the Antiracist Research and Policy Center," Fanta Aw, vice president of campus life, said in the statement. "AU is committed to the vision of the Center and Dr. Kendi's work and we will not be deterred by this cowardly attempt at intimidation."
Images of the posters on campus began to circulate on Twitter.
On Monday morning, American University issued a crime alert and identified a suspect in the incident.
"The male show in this alert is currently a suspect in this incident," the statement read. "He is believed to be a white male, approximately 40 years of age."
The news of the Confederate posters comes months after bananas hanging from strings the shape of nooses were found on campus in another racist incident.
Racist signs hung on campus @AmericanU. This fear tactic will not stop antiracists on campus. We are strong and we are together #antiracism pic.twitter.com/EQRjDllcmp
- Michael T. Barry Jr. (@MTBarryJr) September 27, 2017
AUPD has issued a crime alert for a bias-related defacing property incident that occurred last night. https://t.co/4WvrgCeo9K pic.twitter.com/4NpiVZlQtW
- AU Public Safety (@AUPublicSafety) September 27, 2017