JONESBORO, Ark. (TheBlaze/AP) — Arkansas State University has lifted a lockdown of its Jonesboro campus that followed reports of armed men near the student union.

The university lifted the lockdown about an hour after it took effect after school and city police determined there was no threat.

The university sent an emergency alert shortly before 2 p.m. Sunday saying two armed men were seen near the student union. A later message said three men wearing all black were seen.

University police and area law enforcement were clearing campus buildings, the school’s website said before the lockdown was lifted.

A pair of students sent out the following tweets during the situation:

Neither ASU nor Jonesboro police immediately returned phone calls seeking comment.

The lockdown was the second at the school in the last three months.

A man with a shotgun drove onto campus on Dec. 10. That incident ended peacefully as the man eventually surrendered.

This story has been updated.