At least seven historically Black colleges and universities across the country went into lockdown on Thursday after institutions received threats, which they did not elaborate on.

Southern University and A&M College in Louisiana asked those on campus to shelter in place in response to a “potential threat to campus safety.”

The lockdown applied to the “entire Baton Rouge landmass,” including the Southern University Law Center, the Agricultural Research and Extension Center, and the university’s Laboratory School, according to a statement from the institution.

The lockdown lifted in the afternoon, but all classes and campus activities were canceled through the weekend.

Alabama State University also received a “terroristic threat,” university officials told local media outlets, and shut down campus as law enforcement officials checked buildings. The university sent an all-clear notice later in the day, noting that “the immediate threat has been resolved,” but told students to continue to shelter in place.

Two HBCUs in Virginia were also targeted.

Virginia State University went into lockdown while local, state and federal law enforcement agencies investigated the credibility of a threat received earlier that day, according to a message from the Virginia State University Office of Communications and University Relations. University officials assured students, “No injuries or incidents have been reported in connection with the threat” and said they would be provided with meals in university housing during the lockdown.

Hampton University canceled all activities and classes for both Thursday and Friday in response to a potential threat. Students were discouraged from moving across campus unless absolutely necessary, and all nonessential employees were told to “evacuate immediately” in a notice on the university’s website.

A threat at Bethune-Cookman University in Florida also forced the university to cancel classes and go into lockdown. A notice from the university told students to go to their dorms and faculty and staff members to leave campus.

Spelman College in Atlanta didn’t receive a threat but issued a shelter-in-place order because of its proximity to Clark-Atlanta University, which did. The order was lifted around 2 p.m.

Howard University, in Washington, D.C., assured students the institution hadn’t received any threats but would maintain “heightened security.”

“At Howard, we denounce all acts of hate designed to foster fear in our communities,” an update from the university read. “Howard stands in solidarity with our fellow HBCUs.”

A predominantly white institution, the University of Central Florida, also reported receiving a threat Thursday. The Orlando Sentinel, which obtained a copy via an anonymous tipster, reported that the expletive-laden message threatened Black students and referenced the killing of Iryna Zarutska, a Ukrainian refugee stabbed on a train in North Carolina.

A message from the UCF Police Department Thursday afternoon said, “Similar messages have been reported at other universities around the country.” The police department added it was working with the Federal Bureau of Investigation to assess the threat but does not consider it “to be credible.”

In what appears to be an unrelated incident, the U.S. Naval Academy in Annapolis, Md., went on lockdown Thursday evening after suspicious activity was reported on campus, The Baltimore Banner reported. One person was injured as Naval Security Forces cleared a building.

Florida A&M University, an HBCU, did not receive any threats but put out a statement of solidarity with institutions on lockdown.

Rep. Troy A. Carter, a Democrat from Louisiana, posted on X that he was “outraged and deeply disturbed” by the threats to HBCUs.

“These reprehensible acts are not only an attack on institutions of higher learning—they are an attack on our history, our culture, and the promise of opportunity that HBCUs represent for generations of students,” Carter wrote. In a statement, he called on the federal government “to utilize every available resource to identify, apprehend, and prosecute those responsible.”

The Congressional Black Caucus also put out a statement calling for action from the U.S. Department of Justice and FBI. Caucus members described the threats as a “chilling reminder of the relentless racism and extremism that continues to target and terrorize Black communities in this country.”

The rash of violent threats is reminiscent of a wave of bomb threats that targeted HBCUs in 2022 and prompted the FBI to get involved. The HBCU campus lockdowns also come on the heels of a series of false calls to colleges and universities about active shooters last month; an online extremist group claimed responsibility for the hoaxes.