(The Hill) — Seven historically Black colleges and universities reported bomb threats hours apart Tuesday night, forcing evacuations and lockdowns of the campuses before law enforcement issued an all-clear.

The threats were reported at Howard University in Washington, D.C.; Norfolk State University in Virginia; the University of Arkansas at Pine Bluffs (UAPB); Florida Memorial University; North Carolina Central University (NCCU); Xavier University in Louisiana, and Prairie View A&M University in Texas.

The threats appear to have been unfounded, with no universities reporting an actual bomb, suspicious package or attack as of Wednesday morning. But many of the colleges ordered full evacuations for the students still on campus during the winter break. 

Xavier University reported a bomb threat around 3 p.m. on Tuesday, according to local outlet NOLA.com. That was followed by threats made at UAPB, Prairie View A&M and NCCU around 5 p.m., per tweets and statements from the schools.

Florida Memorial University staff then announced at 7:35 p.m. that the school had received a bomb threat, according to an email shared on Twitter.

Norfolk State and Howard also reported that they had received threats. Both colleges confirmed on Twitter that their campuses had been given the all clear by Tuesday night.

Norfolk State officials announced on Twitter that students had been “secured in a hotel and dorms remain closed until 8 AM Wednesday.”