At least eight historically Black colleges and universities received bomb threats Tuesday, school officials said, triggering abrupt evacuations of students and employees.

Spelman College, the University of Arkansas at Pine Bluff, Florida Memorial University, Howard University, Norfolk State University, North Carolina Central University, Prairie View A&M University in Texas, and Xavier University of Louisiana reported bomb threats. No explosions occurred.

Multiple schools ordered evacuations or lockdowns and alerted local law enforcement. It was not immediately clear whether the threats were connected or whether they were racially motivated. By early Wednesday, all of the schools had released all-clear notices to their communities.

In many cases, the threats arrived in the midst of winter break, or to campuses much emptier than usual as school officials sought to keep people safe amid the pandemic.

“Although the threat was unfounded we ask that everyone remains vigilant,” a statement

from the University of Arkansas at Pine Bluff said, adding that the full student body hadn’t yet re- turned from the holiday break but those who were there were relocated off campus.

At Howard, the start of the semester was delayed due to a surge of coronavirus cases in the D.C. area in December, so students were not on campus. They can begin moving in Jan. 14 for classes expected to begin Jan. 18. Administrative operations had resumed Monday, but most staff members are working remotely at the moment, according to a Howard spokeswoman, Kimberly Holmes-Iverson.

The university said D.C. police contacted Howard’s Department of Public Safety on Tuesday afternoon to alert them that their dispatch center had received an anonymous call saying that two bombs had been placed in Howard’s administration building. The two departments secured the perimeter, according to a statement from the university, evacuated the building and searched the area. No active devices were found, and the area was cleared.

Spelman College officials announced Wednesday that its Department of Public Safety and the Atlanta Police Department responded to a potential bomb threat in the Manley College Center on campus Tuesday. The building was secured after a search; no device was found, and Atlanta police continue to investigate.

A bomb threat was called in to Norfolk State University on Tuesday evening, school officials said in a statement. The university’s police chief, Brian Covington, said police relocated all students, faculty and staff to a safe location until the campus was cleared. The FBI and Norfolk Po- lice Department are helping the university’s police department in the investigation.

Whitney Cruse, a spokeswoman for the Bureau of Alcohol, Tobacco, Firearms and Explosives’ Washington Field Office said they are collaborating with other law enforcement agencies in areas where the threats occurred.

“We have no current evidence that HB- CU’s are specifically targeted,” Cruse said in a statement. “We are monitoring the events closely.”

The threatening messages arrived during the afternoon or evening, schools said. Pine Bluff officials said their school received a threat about 5:15 p.m.

Shortly after that, at about 5:30 p.m., North Carolina Central University police received a call regarding a bomb threat on campus.

The campus was immediately locked down, according to school officials, with an alert sent to students and employees. Multiple agencies, including ATF, law enforcement and fire departments worked with university police to ensure all buildings were cleared, according to a university statement. An all-clear was issued at 9:15 p.m.