GRAMBLING, La. (AP) — Grambling State University locked down its campus Friday after a series of fights and reports of at least one gunshot.

Nobody was hit by a bullet. One student’s face was slightly cut, university spokesman Ralph Wilson said. Five people were arrested.

Although officials initially said at least one shot was fired, Wilson said investigators did not find a gun and no witnesses reported seeing one. Many students reported hearing a bang that might have been a gunshot or a firecracker, he said.

He said the bang occurred about 1 p.m., during the last of three fights which broke out within 1 1/2 hours.

Wilson said students were notified by the campus alert system about 2 p.m. that classes would end at 3 p.m. and resume Monday. However, the campus newspaper, The Gramblinite, reported on its Web site that the FirstCall system text message did not arrive until 5:24 p.m.

Students were kept inside their dormitories for about 25 minutes, and nobody was allowed on campus Friday night without a Grambling ID, Wilson said. He said officials were to decide Saturday morning whether to continue that restriction.

The fights broke out on the last day of Grambling’s spring festival and canceled late afternoon and evening events.

The confrontation involved both students and people not enrolled at Grambling, said Horace A. Judson, the university’s president.

Judson said he was out of town when the incident occurred, but all was quiet when he returned to campus Friday evening.

‘‘The campus is safe,’’ he said.

Students were allowed to walk on campus and go to the dining hall, Judson said. ‘‘We’re not allowing large congregations,’’ he added.

Grambling city police and Lincoln Parish sheriff’s deputies joined GSU police on the campus.

Five people were arrested in connection with the fight, said Michael McKinley, Judson’s executive assistant. McKinley said two were booked with resisting officers and disturbing the peace, one was jailed on a charge of possessing marijuana with intent to distribute, and two others were released after being given court summons for unspecified charges. He had no other details.

Wilson said the three fights were near two dormitories.

Police were still investigating, but reports indicated that people who were involved in off-campus fights with students Thursday night came onto campus Friday and resumed the fight, Judson said.

The incident occurred on the last day of Grambling’s spring festival, canceling its final event — a fraternity and sorority step show.

It was the first disruption of the festival since Grambling moved it from weekends to weekdays four or five years ago to minimize the number of ‘‘outside people’’ on campus, Judson said.