NEWBURYPORT — A police K-9 unit swept inside and around Newburyport High School on Wednesday afternoon, a day after a round of ammunition was found by a student running on the school’s turf field, according to school and police officials.

The student brought the ammunition to the police station and out of what School Superintendent Sean Gallagher called “an abundance of caution,” a thorough search was made by local and area police.

Gallagher, who announced the bullet and the subsequent search in a phone message to parents, said no other rounds or dangerous items were found and there was “no danger or credible threat towards anyone.”