The Associated Press is reporting that the North American Aerospace Defense Command (NORAD) headquarters near Colorado Springs was evacuated for around four and a half hours on Thursday. The evacuation of around 1,500 people took place because of five “suspicious” or “out of place” packages that were found at the site.

Personnel were called in to examine the packages and determined they were not filled with any potentially harmful substances. UPI later reported that military dogs were brought in to stiff the packages, which were subsequently moved to another location.

According to UPI, when officials finally opened the package they found only “office supplies.” NORAD stated that its essential operations were not disrupted by the event, and that the control room team was able to operate at a nearby backup location.

NORAD is a joint organization that provides aerospace defense for the U.S. and Canada. The Royal Canadian Air Force and the U.S. Air Force use the facility to coordinate aerospace warning systems and air sovereignty throughout North America.