Student shot on Widener University campus in Pa.

CHESTER, Pa. (AP) — A gunman shot a college student sitting in the parking lot of Widener University's athletic center Monday, but officials said the campus was secure, even as they warned students to remain inside as police searched across the city for the shooter

Chester police said the student was shot once in the side by an unknown gunman around 8:45 p.m. Monday and he called 911 himself. The victim, who wasn't identified, was listed in critical, but stable condition at Crozer-Chester Medical Center Tuesday morning after undergoing surgery Monday night, the hospital said.

Widener said in a statement on its website that Chester police had secured the campus and did not believe there was an "active shooter" on the campus, but asked students to remain inside until 6 a.m.

Dan Hanson, a spokesman for the university, said Tuesday morning that "all indications are this was not a random act of violence." He would not release further details of the investigation.

Chester police were reviewing surveillance footage and were using K-9 units to track the suspect, who they believe fled into a residential neighborhood adjacent to the athletic complex, on the edge of the campus.

Police told reporters that they found one shell casing on the scene and believe the shooter used a revolver.

Widener University is a private, co-ed university located in Chester, Delaware County, 14 miles south of Philadelphia. The university also has three other campuses in Harrisburg, Exton and Wilmington, Del.