BATON ROUGE - Southern University's campus was shut down early Monday morning amid a series of reported threats at historically Black colleges across the country. 

A message sent out by the university shortly before 7 a.m. said the Baton Rouge campus was placed on lockdown and classes were canceled. The campus initially warned students living on campus to stay in their dorms. 

The university gave an "all clear" shortly after 1 p.m. Monday, though campus remained closed for the day. Read the latest statement from the university below.

After a thorough search by the Southern University Police Department and external law enforcement agencies, the Southern University land mass (Southern University and A&M College, Southern University Law Center, Southern University Agricultural Research and Extension Center, and Southern University Laboratory School) has received an “all clear” in the wake of this morning’s bomb threat. The campus remains closed for classes and normal operations through today. Residential students may resume accessing dining and fitness center facilities.

Normal operations and classes will resume on Tuesday, Feb. 1.

The threat was one of at least six sent to HBCU campuses early Monday, according to CNN. Similar reports were made at Howard University, Bethune-Cookman University, Albany State University, Bowie State University and Delaware State University. 

According to Politico, the Bureau of Alcohol, Tobacco, Firearms and Explosives is part of the federal investigation into the threats. 

It's the second time in the past month that multiple historically Black universities received threats. At least three HBCUs were similarly targeted on Jan. 3, though nothing was found on any of those campuses at the time.