TALLAHASSEE, Fla. — A gunman opened fire early today at a Florida State University library sending hundreds of students who had been up all night studying for exams scrambling for cover in the book aisles and barricading themselves in with desks.

Three students were wounded before police killed the gunman in a shootout, authorities said.

Police and FSU officials called the shooting an “isolated incident,” but have not released many details, including how far the suspected gunman made it into Strozier Library. FSU’s campus is located less than a mile from downtown Tallahassee and the state Capitol.

“This person just for whatever reason produced a handgun and then began shooting students in the library,” FSU Police Chief David Perry said.

The attack started soon after midnight when students inside the multistory library heard about half a dozen gunshots. Students began screaming that someone was shooting at them and flipped over chairs in their race to take cover.

Other students hid in the book aisles and some barricaded themselves in rooms.

Two of the victims were taken to a hospital. FSU officials said a third student was only grazed by a bullet and was treated at the scene and released.

Tallahassee and Florida State University police confronted the gunman just outside the library that is in the middle of the campus and ordered him to drop his handgun, but he fired a shot at them and they unleashed a volley of shots, Tallahassee Police spokesman Dave Northway said.

Hours after the shooting, detectives could be seen inspecting the body of the suspected gunman, who was lying face down at the top of an access ramp just outside the library. A gray baseball cap lay near his head.

The shooting prompted a campus alert that urged students to take shelter and stay away from doors and windows. After the shooting, FSU officials announced classes would be canceled today.