TULSA, Oklahoma - Metro Christian Academy in Tulsa was on lockdown Thursday afternoon after school officials discovered ammunition at the school, police said.

About 1 p.m., officers searched every locker and cars on school grounds in the 6300 block of South Trenton Avenue, to look for weapons to be used with a .22-caliber bullet found by a student in a hallway.

"Tulsa Police officers and a Tulsa Police canine searched the school as well as all the lockers," TPD said in a statement to media. "There were no firearms or additional bullets that were found during the search."

The school said no students were in danger or threatened, and that the lockdown was a precautionary measure.

Students were released about a half an hour late Thursday afternoon.

Metro Christian is a private, interdenominational college preparatory school that serves students from preschool to 12th grade.