(Photo: Live8 Screen Shot)A possible gunman has been spotted on the IUPUI campus, sparking a lockdown as authorities look for the suspect.

An Indiana campus was put on lockdown on Tuesday after a possible gunman was spotted on the grounds. According to reports, the Indiana University Purdue University-Indianapolis campus is currently being searched extensively with a gunman thought to be loose somewhere on the grounds.

A female student reported seeing a man carrying a long gun in the campus parking lot at about 12.30 p.m. local time, and called the police, according to The Associated Press.

Authorities immediately put the campus on lockdown and told staff and students to all seek shelter and if possible avoid the campus all together.

The Indiana University Purdue University-Indianapolis sent out a message via its Twitter account to staff and students explaining the alert. The post stated, "IUPUI Alert! Man with long gun seen in lot at Barnhill and Vermont. Seek Shelter."

According to media reports, police were on the scene within minutes of the gunman sighting being reported, however, after an extensive search of the parking lot area they were unable to find any gunman.

Police have also said that another eye-witness has reported to them that they spotted a man matching the description given by the first student somewhere else on campus. As of yet they have not found the suspect and are still conducting their searches of the area.

Already several university buildings have been completely cleared and emptied out, and after thorough searches have not led to the capture of the suspect.

The NCAA headquarters, as well as the Riley Hospital for Children, and the Crispus Attucks High School, have all also been put on lockdown, according to various media reports.

Here is a video report into the incident: