Gunman on the run after US university professor shot dead on campus

A gunman is on the run in the US after shooting dead a professor at a Mississippi university.

Delta State University in Cleveland was put into lockdown around 10.45am local time (2.45am AEST) after history professor Ethan Schmidt was killed inside an office at Jobe Hall on campus.

Police have named university employee Shannon Lamb as a person of interest in the shooting.

Students were urged to take immediate lockdown action from the university's Twitter account.

A further tweet from the university confirmed there had been one fatality, and told everyone on campus to stay inside and away from windows.

"MHP, Cleveland Police and Bolivar Sheriff's Department are on campus," another tweet read.

"More information distributed as available."

Authorities believe the suspect is no longer on campus.

Earlier reports of a hostage situation have since been retracted.

Professor Schmidt specialised in Native American and colonial history and directed the first-year seminar program, the Associated Press reports.

The city of Cleveland has just over 12,000 people and is around 70km northeast of Greenville.