EMMAUS. (AP) - An eastern Pennsylvania high school will be closed following a three-hour lockdown that occurred after approximately 50 bullets were found at the school.

Lehigh County District Attorney Jim Martin confirmed that police recovered the .22-caliber bullets on the floor inside Emmaus High School on Thursday. No guns were found and no arrests have been made.

Martin says there was no "imminent threat" during the lockdown, which started at around 8 a.m. Students were dismissed at 11:15 a.m.

East Penn School District officials say the high school will be closed to students and staff on Friday to give police more time to investigate.