Yale University has alerted its campus of an active gunman, reported by an anonymous caller from a local payphone.

Yale sent out an emergency alert on its website at 10:17 a.m. that an anonymous person calling from a Columbus Ave. payphone had spotted someone on or near the school's campus with a gun.

As recently as 11:37 a.m., Yale urged its campus community to stay indoors and seek shelter in the nearest building possible, as well as warning people off-campus to stay away.

NBC Connecticut has live coverage of the event and have reported the investigation and search for the gunman is "very active" and far from being resolved. Initial reports came in just after ten a.m. and the school has now confirmed the reports of the gunman, emphasizing the importance of staying inside.

CLICK HERE to watch NBC Conn.'s live coverage just off of Yale's campus.

Law enforcement officers have set up a perimeter on campus and shut down surrounding streets. NBC Conn.'s on-the-scene reporter said one police officer labeled a potion of Elm Street the "hot zone," an area where they strongly believe the gunman is.

While the campus has seen a good amount of students go home for the holiday break, many people remain on the Ivy League school's campus. NBC Conn. pointed out that Yale is an active campus for faculty and student researchers working through the winter intermission.

The campus is on lockdown, police and media line the perimeter and ambulances are arriving as a precautionary measure.

The official alerts are as follows. Visit Emergency.Yale.edu or follow the school on Twitter for updates as they come in.

11:57 a.m.

"There are confirmed reports of a person with a gun on campus on the Old Campus. The shelter-in-place/lockdown continues.

 Teams from Yale Police, New Haven and the State Police are on the scene and are actively searching for any gunman.

THIS IS NOT A TEST. Call 911 with any information."

11:37 a.m.

"SHELTER IN PLACE/LOCKDOWN REMAINS ON CAMPUS. IF OFF CAMPUS, STAY AWAY."

11:02 a.m.

"Confirmed report of person with a gun on/near Old Campus. SHELTER IN PLACE. This is NOT a test."

10:50 a.m.

"Reports of person with gun on Central Campus. SHELTER IN PLACE until further notice."

10:17 a.m.

"New Haven Police have received an anonymous call from a phone booth in the 300 block of Columbus Avenue (between Howard Avenue and Hallock Street) reporting a person on the Yale campus with a gun. There have been NO confirmations or sightings of this person. Yale and New Haven Police are in the area. If you have information, please call 911 immediately. The Yale Police Department advises those on campus to remain in their current location until there is additional information."