They appeared to be posted on bulletin boards for specific programs, including boards dedicated to the Center for Israel Studies and to American Studies month, as well as one outside the university’s center for diversity and inclusion. Ms. Burwell said that the posters were found in four separate buildings on the university’s Washington campus.

Dr. Kendi, a historian and author who joined the university this year, released a separate statement in which he tried to comfort students, “especially students of color and Jewish students, who may be feeling yet another rush of fear from tonight’s posters.”

“I want you to know that you are a model of triumph,” he wrote. “And when you triumph you become a threat to people who would rather you fail.”

He continued, “If they can’t keep you down by discrimination, then they have attempted to keep you down by terror, by instilling fear in you, in me.”

This is at least the second time this year that racist symbols were discovered on the school’s campus. In May, bananas were found hanging from nooses on campus the same day that a student, Taylor Dumpson, became the first black woman elected student body president. The F.B.I. said at the time that it was helping the university investigate.

Ms. Dumpson and other student government leaders released a statement Tuesday, calling the Confederate posters “horrifying.”

“The significance of this occurring as our country continues to struggle with its history of white supremacy also cannot be ignored,” they said, expressing their support for the investigation “to bring whoever committed this act to justice.”